* #39226: Switch back to pjsip rev 4710
Rev 4716 introduces errors when building for android (miltiple definitions)
diff --git a/jni/pjproject-android/.svn/pristine/c5/c5005fbca1c6a9af3a1ce7ee8a073dc8734b6e32.svn-base b/jni/pjproject-android/.svn/pristine/c5/c5005fbca1c6a9af3a1ce7ee8a073dc8734b6e32.svn-base
new file mode 100644
index 0000000..7e4e549
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c5005fbca1c6a9af3a1ce7ee8a073dc8734b6e32.svn-base
@@ -0,0 +1,26 @@
+# $Id$
+import inc_sip as sip
+import inc_sdp as sdp
+
+sdp = \
+"""
+v=0
+o=- 0 0 IN IP4 127.0.0.1
+s=tester
+c=IN IP4 127.0.0.1
+t=0 0
+m=audio 4000 RTP/AVP 0 101
+a=rtpmap:0 PCMU/8000
+a=sendrecv
+a=rtpmap:101 telephone-event/8000
+a=fmtp:101 0-15
+a=crypto:0 AES_CM_128_HMAC_SHA1_80 inline:WnD7c1ksDGs+dIefCEo8omPg4uO8DYIinNGL5yxQ
+"""
+
+args = "--null-audio --auto-answer 200 --max-calls 1 --use-srtp 1 --srtp-secure 0"
+include = []
+exclude = []
+
+sendto_cfg = sip.SendtoCfg( "caller has used crypto tag zero, callee must accept the call",
+ pjsua_args=args, sdp=sdp, resp_code=200,
+ resp_inc=include, resp_exc=exclude)
diff --git a/jni/pjproject-android/.svn/pristine/c5/c52c7c648d616276fa97996ffd0bccb670523d07.svn-base b/jni/pjproject-android/.svn/pristine/c5/c52c7c648d616276fa97996ffd0bccb670523d07.svn-base
new file mode 100644
index 0000000..ecc0648
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c52c7c648d616276fa97996ffd0bccb670523d07.svn-base
@@ -0,0 +1,3139 @@
+
+
+
+
+
+
+Network Working Group M. Baugher
+Request for Comments: 3711 D. McGrew
+Category: Standards Track Cisco Systems, Inc.
+ M. Naslund
+ E. Carrara
+ K. Norrman
+ Ericsson Research
+ March 2004
+
+
+ The Secure Real-time Transport Protocol (SRTP)
+
+Status of this Memo
+
+ This document specifies an Internet standards track protocol for the
+ Internet community, and requests discussion and suggestions for
+ improvements. Please refer to the current edition of the "Internet
+ Official Protocol Standards" (STD 1) for the standardization state
+ and status of this protocol. Distribution of this memo is unlimited.
+
+Copyright Notice
+
+ Copyright (C) The Internet Society (2004). All Rights Reserved.
+
+Abstract
+
+ This document describes the Secure Real-time Transport Protocol
+ (SRTP), a profile of the Real-time Transport Protocol (RTP), which
+ can provide confidentiality, message authentication, and replay
+ protection to the RTP traffic and to the control traffic for RTP, the
+ Real-time Transport Control Protocol (RTCP).
+
+Table of Contents
+
+ 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
+ 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
+ 2. Goals and Features . . . . . . . . . . . . . . . . . . . . . . 4
+ 2.1. Features . . . . . . . . . . . . . . . . . . . . . . . . 5
+ 3. SRTP Framework . . . . . . . . . . . . . . . . . . . . . . . . 5
+ 3.1. Secure RTP . . . . . . . . . . . . . . . . . . . . . . . 6
+ 3.2. SRTP Cryptographic Contexts. . . . . . . . . . . . . . . 7
+ 3.2.1. Transform-independent parameters . . . . . . . . 8
+ 3.2.2. Transform-dependent parameters . . . . . . . . . 10
+ 3.2.3. Mapping SRTP Packets to Cryptographic Contexts . 10
+ 3.3. SRTP Packet Processing . . . . . . . . . . . . . . . . . 11
+ 3.3.1. Packet Index Determination, and ROC, s_l Update. 13
+ 3.3.2. Replay Protection. . . . . . . . . . . . . . . . 15
+ 3.4. Secure RTCP . . . . . . . . . . . . . . . . . . . . . . . 15
+
+
+
+Baugher, et al. Standards Track [Page 1]
+
+RFC 3711 SRTP March 2004
+
+
+ 4. Pre-Defined Cryptographic Transforms . . . . . . . . . . . . . 19
+ 4.1. Encryption . . . . . . . . . . . . . . . . . . . . . . . 19
+ 4.1.1. AES in Counter Mode. . . . . . . . . . . . . . . 21
+ 4.1.2. AES in f8-mode . . . . . . . . . . . . . . . . . 22
+ 4.1.3. NULL Cipher. . . . . . . . . . . . . . . . . . . 25
+ 4.2. Message Authentication and Integrity . . . . . . . . . . 25
+ 4.2.1. HMAC-SHA1. . . . . . . . . . . . . . . . . . . . 25
+ 4.3. Key Derivation . . . . . . . . . . . . . . . . . . . . . 26
+ 4.3.1. Key Derivation Algorithm . . . . . . . . . . . . 26
+ 4.3.2. SRTCP Key Derivation . . . . . . . . . . . . . . 28
+ 4.3.3. AES-CM PRF . . . . . . . . . . . . . . . . . . . 28
+ 5. Default and mandatory-to-implement Transforms. . . . . . . . . 28
+ 5.1. Encryption: AES-CM and NULL. . . . . . . . . . . . . . . 29
+ 5.2. Message Authentication/Integrity: HMAC-SHA1. . . . . . . 29
+ 5.3. Key Derivation: AES-CM PRF . . . . . . . . . . . . . . . 29
+ 6. Adding SRTP Transforms . . . . . . . . . . . . . . . . . . . . 29
+ 7. Rationale. . . . . . . . . . . . . . . . . . . . . . . . . . . 30
+ 7.1. Key derivation . . . . . . . . . . . . . . . . . . . . . 30
+ 7.2. Salting key. . . . . . . . . . . . . . . . . . . . . . . 30
+ 7.3. Message Integrity from Universal Hashing . . . . . . . . 31
+ 7.4. Data Origin Authentication Considerations. . . . . . . . 31
+ 7.5. Short and Zero-length Message Authentication . . . . . . 32
+ 8. Key Management Considerations. . . . . . . . . . . . . . . . . 33
+ 8.1. Re-keying . . . . . . . . . . . . . . . . . . . . . . . 34
+ 8.1.1. Use of the <From, To> for re-keying. . . . . . . 34
+ 8.2. Key Management parameters. . . . . . . . . . . . . . . . 35
+ 9. Security Considerations. . . . . . . . . . . . . . . . . . . . 37
+ 9.1. SSRC collision and two-time pad. . . . . . . . . . . . . 37
+ 9.2. Key Usage. . . . . . . . . . . . . . . . . . . . . . . . 38
+ 9.3. Confidentiality of the RTP Payload . . . . . . . . . . . 39
+ 9.4. Confidentiality of the RTP Header. . . . . . . . . . . . 40
+ 9.5. Integrity of the RTP payload and header. . . . . . . . . 40
+ 9.5.1. Risks of Weak or Null Message Authentication. . . 42
+ 9.5.2. Implicit Header Authentication . . . . . . . . . 43
+ 10. Interaction with Forward Error Correction mechanisms. . . . . 43
+ 11. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 43
+ 11.1. Unicast. . . . . . . . . . . . . . . . . . . . . . . . . 43
+ 11.2. Multicast (one sender) . . . . . . . . . . . . . . . . . 44
+ 11.3. Re-keying and access control . . . . . . . . . . . . . . 45
+ 11.4. Summary of basic scenarios . . . . . . . . . . . . . . . 46
+ 12. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 46
+ 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 47
+ 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 47
+ 14.1. Normative References . . . . . . . . . . . . . . . . . . 47
+ 14.2. Informative References . . . . . . . . . . . . . . . . . 48
+ Appendix A: Pseudocode for Index Determination . . . . . . . . . . 51
+ Appendix B: Test Vectors . . . . . . . . . . . . . . . . . . . . . 51
+ B.1. AES-f8 Test Vectors. . . . . . . . . . . . . . . . . . . 51
+
+
+
+Baugher, et al. Standards Track [Page 2]
+
+RFC 3711 SRTP March 2004
+
+
+ B.2. AES-CM Test Vectors. . . . . . . . . . . . . . . . . . . 52
+ B.3. Key Derivation Test Vectors. . . . . . . . . . . . . . . 53
+ Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 55
+ Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 56
+
+1. Introduction
+
+ This document describes the Secure Real-time Transport Protocol
+ (SRTP), a profile of the Real-time Transport Protocol (RTP), which
+ can provide confidentiality, message authentication, and replay
+ protection to the RTP traffic and to the control traffic for RTP,
+ RTCP (the Real-time Transport Control Protocol) [RFC3350].
+
+ SRTP provides a framework for encryption and message authentication
+ of RTP and RTCP streams (Section 3). SRTP defines a set of default
+ cryptographic transforms (Sections 4 and 5), and it allows new
+ transforms to be introduced in the future (Section 6). With
+ appropriate key management (Sections 7 and 8), SRTP is secure
+ (Sections 9) for unicast and multicast RTP applications (Section 11).
+
+ SRTP can achieve high throughput and low packet expansion. SRTP
+ proves to be a suitable protection for heterogeneous environments
+ (mix of wired and wireless networks). To get such features, default
+ transforms are described, based on an additive stream cipher for
+ encryption, a keyed-hash based function for message authentication,
+ and an "implicit" index for sequencing/synchronization based on the
+ RTP sequence number for SRTP and an index number for Secure RTCP
+ (SRTCP).
+
+1.1. Notational Conventions
+
+ The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+ "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+ document are to be interpreted as described in [RFC2119]. The
+ terminology conforms to [RFC2828] with the following exception. For
+ simplicity we use the term "random" throughout the document to denote
+ randomly or pseudo-randomly generated values. Large amounts of
+ random bits may be difficult to obtain, and for the security of SRTP,
+ pseudo-randomness is sufficient [RFC1750].
+
+ By convention, the adopted representation is the network byte order,
+ i.e., the left most bit (octet) is the most significant one. By XOR
+ we mean bitwise addition modulo 2 of binary strings, and || denotes
+ concatenation. In other words, if C = A || B, then the most
+ significant bits of C are the bits of A, and the least significant
+ bits of C equal the bits of B. Hexadecimal numbers are prefixed by
+ 0x.
+
+
+
+
+Baugher, et al. Standards Track [Page 3]
+
+RFC 3711 SRTP March 2004
+
+
+ The word "encryption" includes also use of the NULL algorithm (which
+ in practice does leave the data in the clear).
+
+ With slight abuse of notation, we use the terms "message
+ authentication" and "authentication tag" as is common practice, even
+ though in some circumstances, e.g., group communication, the service
+ provided is actually only integrity protection and not data origin
+ authentication.
+
+2. Goals and Features
+
+ The security goals for SRTP are to ensure:
+
+ * the confidentiality of the RTP and RTCP payloads, and
+
+ * the integrity of the entire RTP and RTCP packets, together with
+ protection against replayed packets.
+
+ These security services are optional and independent from each other,
+ except that SRTCP integrity protection is mandatory (malicious or
+ erroneous alteration of RTCP messages could otherwise disrupt the
+ processing of the RTP stream).
+
+ Other, functional, goals for the protocol are:
+
+ * a framework that permits upgrading with new cryptographic
+ transforms,
+
+ * low bandwidth cost, i.e., a framework preserving RTP header
+ compression efficiency,
+
+ and, asserted by the pre-defined transforms:
+
+ * a low computational cost,
+
+ * a small footprint (i.e., small code size and data memory for
+ keying information and replay lists),
+
+ * limited packet expansion to support the bandwidth economy goal,
+
+ * independence from the underlying transport, network, and physical
+ layers used by RTP, in particular high tolerance to packet loss
+ and re-ordering.
+
+ These properties ensure that SRTP is a suitable protection scheme for
+ RTP/RTCP in both wired and wireless scenarios.
+
+
+
+
+
+Baugher, et al. Standards Track [Page 4]
+
+RFC 3711 SRTP March 2004
+
+
+2.1. Features
+
+ Besides the above mentioned direct goals, SRTP provides for some
+ additional features. They have been introduced to lighten the burden
+ on key management and to further increase security. They include:
+
+ * A single "master key" can provide keying material for
+ confidentiality and integrity protection, both for the SRTP stream
+ and the corresponding SRTCP stream. This is achieved with a key
+ derivation function (see Section 4.3), providing "session keys"
+ for the respective security primitive, securely derived from the
+ master key.
+
+ * In addition, the key derivation can be configured to periodically
+ refresh the session keys, which limits the amount of ciphertext
+ produced by a fixed key, available for an adversary to
+ cryptanalyze.
+
+ * "Salting keys" are used to protect against pre-computation and
+ time-memory tradeoff attacks [MF00] [BS00].
+
+ Detailed rationale for these features can be found in Section 7.
+
+3. SRTP Framework
+
+ RTP is the Real-time Transport Protocol [RFC3550]. We define SRTP as
+ a profile of RTP. This profile is an extension to the RTP
+ Audio/Video Profile [RFC3551]. Except where explicitly noted, all
+ aspects of that profile apply, with the addition of the SRTP security
+ features. Conceptually, we consider SRTP to be a "bump in the stack"
+ implementation which resides between the RTP application and the
+ transport layer. SRTP intercepts RTP packets and then forwards an
+ equivalent SRTP packet on the sending side, and intercepts SRTP
+ packets and passes an equivalent RTP packet up the stack on the
+ receiving side.
+
+ Secure RTCP (SRTCP) provides the same security services to RTCP as
+ SRTP does to RTP. SRTCP message authentication is MANDATORY and
+ thereby protects the RTCP fields to keep track of membership, provide
+ feedback to RTP senders, or maintain packet sequence counters. SRTCP
+ is described in Section 3.4.
+
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 5]
+
+RFC 3711 SRTP March 2004
+
+
+3.1. Secure RTP
+
+ The format of an SRTP packet is illustrated in Figure 1.
+
+ 0 1 2 3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<+
+ |V=2|P|X| CC |M| PT | sequence number | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | timestamp | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | synchronization source (SSRC) identifier | |
+ +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
+ | contributing source (CSRC) identifiers | |
+ | .... | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | RTP extension (OPTIONAL) | |
+ +>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | | payload ... | |
+ | | +-------------------------------+ |
+ | | | RTP padding | RTP pad count | |
+ +>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<+
+ | ~ SRTP MKI (OPTIONAL) ~ |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | : authentication tag (RECOMMENDED) : |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | |
+ +- Encrypted Portion* Authenticated Portion ---+
+
+ Figure 1. The format of an SRTP packet. *Encrypted Portion is the
+ same size as the plaintext for the Section 4 pre-defined transforms.
+
+ The "Encrypted Portion" of an SRTP packet consists of the encryption
+ of the RTP payload (including RTP padding when present) of the
+ equivalent RTP packet. The Encrypted Portion MAY be the exact size
+ of the plaintext or MAY be larger. Figure 1 shows the RTP payload
+ including any possible padding for RTP [RFC3550].
+
+ None of the pre-defined encryption transforms uses any padding; for
+ these, the RTP and SRTP payload sizes match exactly. New transforms
+ added to SRTP (following Section 6) may require padding, and may
+ hence produce larger payloads. RTP provides its own padding format
+ (as seen in Fig. 1), which due to the padding indicator in the RTP
+ header has merits in terms of compactness relative to paddings using
+ prefix-free codes. This RTP padding SHALL be the default method for
+ transforms requiring padding. Transforms MAY specify other padding
+ methods, and MUST then specify the amount, format, and processing of
+ their padding. It is important to note that encryption transforms
+
+
+
+Baugher, et al. Standards Track [Page 6]
+
+RFC 3711 SRTP March 2004
+
+
+ that use padding are vulnerable to subtle attacks, especially when
+ message authentication is not used [V02]. Each specification for a
+ new encryption transform needs to carefully consider and describe the
+ security implications of the padding that it uses. Message
+ authentication codes define their own padding, so this default does
+ not apply to authentication transforms.
+
+ The OPTIONAL MKI and the RECOMMENDED authentication tag are the only
+ fields defined by SRTP that are not in RTP. Only 8-bit alignment is
+ assumed.
+
+ MKI (Master Key Identifier): configurable length, OPTIONAL. The
+ MKI is defined, signaled, and used by key management. The
+ MKI identifies the master key from which the session
+ key(s) were derived that authenticate and/or encrypt the
+ particular packet. Note that the MKI SHALL NOT identify
+ the SRTP cryptographic context, which is identified
+ according to Section 3.2.3. The MKI MAY be used by key
+ management for the purposes of re-keying, identifying a
+ particular master key within the cryptographic context
+ (Section 3.2.1).
+
+ Authentication tag: configurable length, RECOMMENDED. The
+ authentication tag is used to carry message authentication
+ data. The Authenticated Portion of an SRTP packet
+ consists of the RTP header followed by the Encrypted
+ Portion of the SRTP packet. Thus, if both encryption and
+ authentication are applied, encryption SHALL be applied
+ before authentication on the sender side and conversely on
+ the receiver side. The authentication tag provides
+ authentication of the RTP header and payload, and it
+ indirectly provides replay protection by authenticating
+ the sequence number. Note that the MKI is not integrity
+ protected as this does not provide any extra protection.
+
+3.2. SRTP Cryptographic Contexts
+
+ Each SRTP stream requires the sender and receiver to maintain
+ cryptographic state information. This information is called the
+ "cryptographic context".
+
+ SRTP uses two types of keys: session keys and master keys. By a
+ "session key", we mean a key which is used directly in a
+ cryptographic transform (e.g., encryption or message authentication),
+ and by a "master key", we mean a random bit string (given by the key
+ management protocol) from which session keys are derived in a
+
+
+
+
+
+Baugher, et al. Standards Track [Page 7]
+
+RFC 3711 SRTP March 2004
+
+
+ cryptographically secure way. The master key(s) and other parameters
+ in the cryptographic context are provided by key management
+ mechanisms external to SRTP, see Section 8.
+
+3.2.1. Transform-independent parameters
+
+ Transform-independent parameters are present in the cryptographic
+ context independently of the particular encryption or authentication
+ transforms that are used. The transform-independent parameters of
+ the cryptographic context for SRTP consist of:
+
+ * a 32-bit unsigned rollover counter (ROC), which records how many
+ times the 16-bit RTP sequence number has been reset to zero after
+ passing through 65,535. Unlike the sequence number (SEQ), which
+ SRTP extracts from the RTP packet header, the ROC is maintained by
+ SRTP as described in Section 3.3.1.
+
+ We define the index of the SRTP packet corresponding to a given
+ ROC and RTP sequence number to be the 48-bit quantity
+
+ i = 2^16 * ROC + SEQ.
+
+ * for the receiver only, a 16-bit sequence number s_l, which can be
+ thought of as the highest received RTP sequence number (see
+ Section 3.3.1 for its handling), which SHOULD be authenticated
+ since message authentication is RECOMMENDED,
+
+ * an identifier for the encryption algorithm, i.e., the cipher and
+ its mode of operation,
+
+ * an identifier for the message authentication algorithm,
+
+ * a replay list, maintained by the receiver only (when
+ authentication and replay protection are provided), containing
+ indices of recently received and authenticated SRTP packets,
+
+ * an MKI indicator (0/1) as to whether an MKI is present in SRTP and
+ SRTCP packets,
+
+ * if the MKI indicator is set to one, the length (in octets) of the
+ MKI field, and (for the sender) the actual value of the currently
+ active MKI (the value of the MKI indicator and length MUST be kept
+ fixed for the lifetime of the context),
+
+ * the master key(s), which MUST be random and kept secret,
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 8]
+
+RFC 3711 SRTP March 2004
+
+
+ * for each master key, there is a counter of the number of SRTP
+ packets that have been processed (sent) with that master key
+ (essential for security, see Sections 3.3.1 and 9),
+
+ * non-negative integers n_e, and n_a, determining the length of the
+ session keys for encryption, and message authentication.
+
+ In addition, for each master key, an SRTP stream MAY use the
+ following associated values:
+
+ * a master salt, to be used in the key derivation of session keys.
+ This value, when used, MUST be random, but MAY be public. Use of
+ master salt is strongly RECOMMENDED, see Section 9.2. A "NULL"
+ salt is treated as 00...0.
+
+ * an integer in the set {1,2,4,...,2^24}, the "key_derivation_rate",
+ where an unspecified value is treated as zero. The constraint to
+ be a power of 2 simplifies the session-key derivation
+ implementation, see Section 4.3.
+
+ * an MKI value,
+
+ * <From, To> values, specifying the lifetime for a master key,
+ expressed in terms of the two 48-bit index values inside whose
+ range (including the range end-points) the master key is valid.
+ For the use of <From, To>, see Section 8.1.1. <From, To> is an
+ alternative to the MKI and assumes that a master key is in one-
+ to-one correspondence with the SRTP session key on which the
+ <From, To> range is defined.
+
+ SRTCP SHALL by default share the crypto context with SRTP, except:
+
+ * no rollover counter and s_l-value need to be maintained as the
+ RTCP index is explicitly carried in each SRTCP packet,
+
+ * a separate replay list is maintained (when replay protection is
+ provided),
+
+ * SRTCP maintains a separate counter for its master key (even if the
+ master key is the same as that for SRTP, see below), as a means to
+ maintain a count of the number of SRTCP packets that have been
+ processed with that key.
+
+ Note in particular that the master key(s) MAY be shared between SRTP
+ and the corresponding SRTCP, if the pre-defined transforms (including
+ the key derivation) are used but the session key(s) MUST NOT be so
+ shared.
+
+
+
+
+Baugher, et al. Standards Track [Page 9]
+
+RFC 3711 SRTP March 2004
+
+
+ In addition, there can be cases (see Sections 8 and 9.1) where
+ several SRTP streams within a given RTP session, identified by their
+ synchronization source (SSRCs, which is part of the RTP header),
+ share most of the crypto context parameters (including possibly
+ master and session keys). In such cases, just as in the normal
+ SRTP/SRTCP parameter sharing above, separate replay lists and packet
+ counters for each stream (SSRC) MUST still be maintained. Also,
+ separate SRTP indices MUST then be maintained.
+
+ A summary of parameters, pre-defined transforms, and default values
+ for the above parameters (and other SRTP parameters) can be found in
+ Sections 5 and 8.2.
+
+3.2.2. Transform-dependent parameters
+
+ All encryption, authentication/integrity, and key derivation
+ parameters are defined in the transforms section (Section 4).
+ Typical examples of such parameters are block size of ciphers,
+ session keys, data for the Initialization Vector (IV) formation, etc.
+ Future SRTP transform specifications MUST include a section to list
+ the additional cryptographic context's parameters for that transform,
+ if any.
+
+3.2.3. Mapping SRTP Packets to Cryptographic Contexts
+
+ Recall that an RTP session for each participant is defined [RFC3550]
+ by a pair of destination transport addresses (one network address
+ plus a port pair for RTP and RTCP), and that a multimedia session is
+ defined as a collection of RTP sessions. For example, a particular
+ multimedia session could include an audio RTP session, a video RTP
+ session, and a text RTP session.
+
+ A cryptographic context SHALL be uniquely identified by the triplet
+ context identifier:
+
+ context id = <SSRC, destination network address, destination
+ transport port number>
+
+ where the destination network address and the destination transport
+ port are the ones in the SRTP packet. It is assumed that, when
+ presented with this information, the key management returns a context
+ with the information as described in Section 3.2.
+
+ As noted above, SRTP and SRTCP by default share the bulk of the
+ parameters in the cryptographic context. Thus, retrieving the crypto
+ context parameters for an SRTCP stream in practice may imply a
+ binding to the correspondent SRTP crypto context. It is up to the
+ implementation to assure such binding, since the RTCP port may not be
+
+
+
+Baugher, et al. Standards Track [Page 10]
+
+RFC 3711 SRTP March 2004
+
+
+ directly deducible from the RTP port only. Alternatively, the key
+ management may choose to provide separate SRTP- and SRTCP- contexts,
+ duplicating the common parameters (such as master key(s)). The
+ latter approach then also enables SRTP and SRTCP to use, e.g.,
+ distinct transforms, if so desired. Similar considerations arise
+ when multiple SRTP streams, forming part of one single RTP session,
+ share keys and other parameters.
+
+ If no valid context can be found for a packet corresponding to a
+ certain context identifier, that packet MUST be discarded.
+
+3.3. SRTP Packet Processing
+
+ The following applies to SRTP. SRTCP is described in Section 3.4.
+
+ Assuming initialization of the cryptographic context(s) has taken
+ place via key management, the sender SHALL do the following to
+ construct an SRTP packet:
+
+ 1. Determine which cryptographic context to use as described in
+ Section 3.2.3.
+
+ 2. Determine the index of the SRTP packet using the rollover counter,
+ the highest sequence number in the cryptographic context, and the
+ sequence number in the RTP packet, as described in Section 3.3.1.
+
+ 3. Determine the master key and master salt. This is done using the
+ index determined in the previous step or the current MKI in the
+ cryptographic context, according to Section 8.1.
+
+ 4. Determine the session keys and session salt (if they are used by
+ the transform) as described in Section 4.3, using master key,
+ master salt, key_derivation_rate, and session key-lengths in the
+ cryptographic context with the index, determined in Steps 2 and 3.
+
+ 5. Encrypt the RTP payload to produce the Encrypted Portion of the
+ packet (see Section 4.1, for the defined ciphers). This step uses
+ the encryption algorithm indicated in the cryptographic context,
+ the session encryption key and the session salt (if used) found in
+ Step 4 together with the index found in Step 2.
+
+ 6. If the MKI indicator is set to one, append the MKI to the packet.
+
+ 7. For message authentication, compute the authentication tag for the
+ Authenticated Portion of the packet, as described in Section 4.2.
+ This step uses the current rollover counter, the authentication
+
+
+
+
+
+Baugher, et al. Standards Track [Page 11]
+
+RFC 3711 SRTP March 2004
+
+
+ algorithm indicated in the cryptographic context, and the session
+ authentication key found in Step 4. Append the authentication tag
+ to the packet.
+
+ 8. If necessary, update the ROC as in Section 3.3.1, using the packet
+ index determined in Step 2.
+
+ To authenticate and decrypt an SRTP packet, the receiver SHALL do the
+ following:
+
+ 1. Determine which cryptographic context to use as described in
+ Section 3.2.3.
+
+ 2. Run the algorithm in Section 3.3.1 to get the index of the SRTP
+ packet. The algorithm uses the rollover counter and highest
+ sequence number in the cryptographic context with the sequence
+ number in the SRTP packet, as described in Section 3.3.1.
+
+ 3. Determine the master key and master salt. If the MKI indicator in
+ the context is set to one, use the MKI in the SRTP packet,
+ otherwise use the index from the previous step, according to
+ Section 8.1.
+
+ 4. Determine the session keys, and session salt (if used by the
+ transform) as described in Section 4.3, using master key, master
+ salt, key_derivation_rate and session key-lengths in the
+ cryptographic context with the index, determined in Steps 2 and 3.
+
+ 5. For message authentication and replay protection, first check if
+ the packet has been replayed (Section 3.3.2), using the Replay
+ List and the index as determined in Step 2. If the packet is
+ judged to be replayed, then the packet MUST be discarded, and the
+ event SHOULD be logged.
+
+ Next, perform verification of the authentication tag, using the
+ rollover counter from Step 2, the authentication algorithm
+ indicated in the cryptographic context, and the session
+ authentication key from Step 4. If the result is "AUTHENTICATION
+ FAILURE" (see Section 4.2), the packet MUST be discarded from
+ further processing and the event SHOULD be logged.
+
+ 6. Decrypt the Encrypted Portion of the packet (see Section 4.1, for
+ the defined ciphers), using the decryption algorithm indicated in
+ the cryptographic context, the session encryption key and salt (if
+ used) found in Step 4 with the index from Step 2.
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 12]
+
+RFC 3711 SRTP March 2004
+
+
+ 7. Update the rollover counter and highest sequence number, s_l, in
+ the cryptographic context as in Section 3.3.1, using the packet
+ index estimated in Step 2. If replay protection is provided, also
+ update the Replay List as described in Section 3.3.2.
+
+ 8. When present, remove the MKI and authentication tag fields from
+ the packet.
+
+3.3.1. Packet Index Determination, and ROC, s_l Update
+
+ SRTP implementations use an "implicit" packet index for sequencing,
+ i.e., not all of the index is explicitly carried in the SRTP packet.
+ For the pre-defined transforms, the index i is used in replay
+ protection (Section 3.3.2), encryption (Section 4.1), message
+ authentication (Section 4.2), and for the key derivation (Section
+ 4.3).
+
+ When the session starts, the sender side MUST set the rollover
+ counter, ROC, to zero. Each time the RTP sequence number, SEQ, wraps
+ modulo 2^16, the sender side MUST increment ROC by one, modulo 2^32
+ (see security aspects below). The sender's packet index is then
+ defined as
+
+ i = 2^16 * ROC + SEQ.
+
+ Receiver-side implementations use the RTP sequence number to
+ determine the correct index of a packet, which is the location of the
+ packet in the sequence of all SRTP packets. A robust approach for
+ the proper use of a rollover counter requires its handling and use to
+ be well defined. In particular, out-of-order RTP packets with
+ sequence numbers close to 2^16 or zero must be properly handled.
+
+ The index estimate is based on the receiver's locally maintained ROC
+ and s_l values. At the setup of the session, the ROC MUST be set to
+ zero. Receivers joining an on-going session MUST be given the
+ current ROC value using out-of-band signaling such as key-management
+ signaling. Furthermore, the receiver SHALL initialize s_l to the RTP
+ sequence number (SEQ) of the first observed SRTP packet (unless the
+ initial value is provided by out of band signaling such as key
+ management).
+
+ On consecutive SRTP packets, the receiver SHOULD estimate the index
+ as
+ i = 2^16 * v + SEQ,
+
+ where v is chosen from the set { ROC-1, ROC, ROC+1 } (modulo 2^32)
+ such that i is closest (in modulo 2^48 sense) to the value 2^16 * ROC
+ + s_l (see Appendix A for pseudocode).
+
+
+
+Baugher, et al. Standards Track [Page 13]
+
+RFC 3711 SRTP March 2004
+
+
+ After the packet has been processed and authenticated (when enabled
+ for SRTP packets for the session), the receiver MUST use v to
+ conditionally update its s_l and ROC variables as follows. If
+ v=(ROC-1) mod 2^32, then there is no update to s_l or ROC. If v=ROC,
+ then s_l is set to SEQ if and only if SEQ is larger than the current
+ s_l; there is no change to ROC. If v=(ROC+1) mod 2^32, then s_l is
+ set to SEQ and ROC is set to v.
+
+ After a re-keying occurs (changing to a new master key), the rollover
+ counter always maintains its sequence of values, i.e., it MUST NOT be
+ reset to zero.
+
+ As the rollover counter is 32 bits long and the sequence number is 16
+ bits long, the maximum number of packets belonging to a given SRTP
+ stream that can be secured with the same key is 2^48 using the pre-
+ defined transforms. After that number of SRTP packets have been sent
+ with a given (master or session) key, the sender MUST NOT send any
+ more packets with that key. (There exists a similar limit for SRTCP,
+ which in practice may be more restrictive, see Section 9.2.) This
+ limitation enforces a security benefit by providing an upper bound on
+ the amount of traffic that can pass before cryptographic keys are
+ changed. Re-keying (see Section 8.1) MUST be triggered, before this
+ amount of traffic, and MAY be triggered earlier, e.g., for increased
+ security and access control to media. Recurring key derivation by
+ means of a non-zero key_derivation_rate (see Section 4.3), also gives
+ stronger security but does not change the above absolute maximum
+ value.
+
+ On the receiver side, there is a caveat to updating s_l and ROC: if
+ message authentication is not present, neither the initialization of
+ s_l, nor the ROC update can be made completely robust. The
+ receiver's "implicit index" approach works for the pre-defined
+ transforms as long as the reorder and loss of the packets are not too
+ great and bit-errors do not occur in unfortunate ways. In
+ particular, 2^15 packets would need to be lost, or a packet would
+ need to be 2^15 packets out of sequence before synchronization is
+ lost. Such drastic loss or reorder is likely to disrupt the RTP
+ application itself.
+
+ The algorithm for the index estimate and ROC update is a matter of
+ implementation, and should take into consideration the environment
+ (e.g., packet loss rate) and the cases when synchronization is likely
+ to be lost, e.g., when the initial sequence number (randomly chosen
+ by RTP) is not known in advance (not sent in the key management
+ protocol) but may be near to wrap modulo 2^16.
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 14]
+
+RFC 3711 SRTP March 2004
+
+
+ A more elaborate and more robust scheme than the one given above is
+ the handling of RTP's own "rollover counter", see Appendix A.1 of
+ [RFC3550].
+
+3.3.2. Replay Protection
+
+ Secure replay protection is only possible when integrity protection
+ is present. It is RECOMMENDED to use replay protection, both for RTP
+ and RTCP, as integrity protection alone cannot assure security
+ against replay attacks.
+
+ A packet is "replayed" when it is stored by an adversary, and then
+ re-injected into the network. When message authentication is
+ provided, SRTP protects against such attacks through a Replay List.
+ Each SRTP receiver maintains a Replay List, which conceptually
+ contains the indices of all of the packets which have been received
+ and authenticated. In practice, the list can use a "sliding window"
+ approach, so that a fixed amount of storage suffices for replay
+ protection. Packet indices which lag behind the packet index in the
+ context by more than SRTP-WINDOW-SIZE can be assumed to have been
+ received, where SRTP-WINDOW-SIZE is a receiver-side, implementation-
+ dependent parameter and MUST be at least 64, but which MAY be set to
+ a higher value.
+
+ The receiver checks the index of an incoming packet against the
+ replay list and the window. Only packets with index ahead of the
+ window, or, inside the window but not already received, SHALL be
+ accepted.
+
+ After the packet has been authenticated (if necessary the window is
+ first moved ahead), the replay list SHALL be updated with the new
+ index.
+
+ The Replay List can be efficiently implemented by using a bitmap to
+ represent which packets have been received, as described in the
+ Security Architecture for IP [RFC2401].
+
+3.4. Secure RTCP
+
+ Secure RTCP follows the definition of Secure RTP. SRTCP adds three
+ mandatory new fields (the SRTCP index, an "encrypt-flag", and the
+ authentication tag) and one optional field (the MKI) to the RTCP
+ packet definition. The three mandatory fields MUST be appended to an
+ RTCP packet in order to form an equivalent SRTCP packet. The added
+ fields follow any other profile-specific extensions.
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 15]
+
+RFC 3711 SRTP March 2004
+
+
+ According to Section 6.1 of [RFC3550], there is a REQUIRED packet
+ format for compound packets. SRTCP MUST be given packets according
+ to that requirement in the sense that the first part MUST be a sender
+ report or a receiver report. However, the RTCP encryption prefix (a
+ random 32-bit quantity) specified in that Section MUST NOT be used
+ since, as is stated there, it is only applicable to the encryption
+ method specified in [RFC3550] and is not needed by the cryptographic
+ mechanisms used in SRTP.
+
+ 0 1 2 3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<+
+ |V=2|P| RC | PT=SR or RR | length | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | SSRC of sender | |
+ +>+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
+ | ~ sender info ~ |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | ~ report block 1 ~ |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | ~ report block 2 ~ |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | ~ ... ~ |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | |V=2|P| SC | PT=SDES=202 | length | |
+ | +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
+ | | SSRC/CSRC_1 | |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | ~ SDES items ~ |
+ | +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
+ | ~ ... ~ |
+ +>+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
+ | |E| SRTCP index | |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<+
+ | ~ SRTCP MKI (OPTIONAL) ~ |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | : authentication tag : |
+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
+ | |
+ +-- Encrypted Portion Authenticated Portion -----+
+
+
+ Figure 2. An example of the format of a Secure RTCP packet,
+ consisting of an underlying RTCP compound packet with a Sender Report
+ and SDES packet.
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 16]
+
+RFC 3711 SRTP March 2004
+
+
+ The Encrypted Portion of an SRTCP packet consists of the encryption
+ (Section 4.1) of the RTCP payload of the equivalent compound RTCP
+ packet, from the first RTCP packet, i.e., from the ninth (9) octet to
+ the end of the compound packet. The Authenticated Portion of an
+ SRTCP packet consists of the entire equivalent (eventually compound)
+ RTCP packet, the E flag, and the SRTCP index (after any encryption
+ has been applied to the payload).
+
+ The added fields are:
+
+ E-flag: 1 bit, REQUIRED
+ The E-flag indicates if the current SRTCP packet is
+ encrypted or unencrypted. Section 9.1 of [RFC3550] allows
+ the split of a compound RTCP packet into two lower-layer
+ packets, one to be encrypted and one to be sent in the
+ clear. The E bit set to "1" indicates encrypted packet, and
+ "0" indicates non-encrypted packet.
+
+ SRTCP index: 31 bits, REQUIRED
+ The SRTCP index is a 31-bit counter for the SRTCP packet.
+ The index is explicitly included in each packet, in contrast
+ to the "implicit" index approach used for SRTP. The SRTCP
+ index MUST be set to zero before the first SRTCP packet is
+ sent, and MUST be incremented by one, modulo 2^31, after
+ each SRTCP packet is sent. In particular, after a re-key,
+ the SRTCP index MUST NOT be reset to zero again.
+
+ Authentication Tag: configurable length, REQUIRED
+ The authentication tag is used to carry message
+ authentication data.
+
+ MKI: configurable length, OPTIONAL
+ The MKI is the Master Key Indicator, and functions according
+ to the MKI definition in Section 3.
+
+ SRTCP uses the cryptographic context parameters and packet processing
+ of SRTP by default, with the following changes:
+
+ * The receiver does not need to "estimate" the index, as it is
+ explicitly signaled in the packet.
+
+ * Pre-defined SRTCP encryption is as specified in Section 4.1, but
+ using the definition of the SRTCP Encrypted Portion given in this
+ section, and using the SRTCP index as the index i. The encryption
+ transform and related parameters SHALL by default be the same
+ selected for the protection of the associated SRTP stream(s),
+ while the NULL algorithm SHALL be applied to the RTCP packets not
+ to be encrypted. SRTCP may have a different encryption transform
+
+
+
+Baugher, et al. Standards Track [Page 17]
+
+RFC 3711 SRTP March 2004
+
+
+ than the one used by the corresponding SRTP. The expected use for
+ this feature is when the former has NULL-encryption and the latter
+ has a non NULL-encryption.
+
+ The E-flag is assigned a value by the sender depending on whether the
+ packet was encrypted or not.
+
+ * SRTCP decryption is performed as in Section 4, but only if the E
+ flag is equal to 1. If so, the Encrypted Portion is decrypted,
+ using the SRTCP index as the index i. In case the E-flag is 0,
+ the payload is simply left unmodified.
+
+ * SRTCP replay protection is as defined in Section 3.3.2, but using
+ the SRTCP index as the index i and a separate Replay List that is
+ specific to SRTCP.
+
+ * The pre-defined SRTCP authentication tag is specified as in
+ Section 4.2, but with the Authenticated Portion of the SRTCP
+ packet given in this section (which includes the index). The
+ authentication transform and related parameters (e.g., key size)
+ SHALL by default be the same as selected for the protection of the
+ associated SRTP stream(s).
+
+ * In the last step of the processing, only the sender needs to
+ update the value of the SRTCP index by incrementing it modulo 2^31
+ and for security reasons the sender MUST also check the number of
+ SRTCP packets processed, see Section 9.2.
+
+ Message authentication for RTCP is REQUIRED, as it is the control
+ protocol (e.g., it has a BYE packet) for RTP.
+
+ Precautions must be taken so that the packet expansion in SRTCP (due
+ to the added fields) does not cause SRTCP messages to use more than
+ their share of RTCP bandwidth. To avoid this, the following two
+ measures MUST be taken:
+
+ 1. When initializing the RTCP variable "avg_rtcp_size" defined in
+ chapter 6.3 of [RFC3550], it MUST include the size of the fields
+ that will be added by SRTCP (index, E-bit, authentication tag, and
+ when present, the MKI).
+
+ 2. When updating the "avg_rtcp_size" using the variable "packet_size"
+ (section 6.3.3 of [RFC3550]), the value of "packet_size" MUST
+ include the size of the additional fields added by SRTCP.
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 18]
+
+RFC 3711 SRTP March 2004
+
+
+ With these measures in place the SRTCP messages will not use more
+ than the allotted bandwidth. The effect of the size of the added
+ fields on the SRTCP traffic will be that messages will be sent with
+ longer packet intervals. The increase in the intervals will be
+ directly proportional to size of the added fields. For the pre-
+ defined transforms, the size of the added fields will be at least 14
+ octets, and upper bounded depending on MKI and the authentication tag
+ sizes.
+
+4. Pre-Defined Cryptographic Transforms
+
+ While there are numerous encryption and message authentication
+ algorithms that can be used in SRTP, below we define default
+ algorithms in order to avoid the complexity of specifying the
+ encodings for the signaling of algorithm and parameter identifiers.
+ The defined algorithms have been chosen as they fulfill the goals
+ listed in Section 2. Recommendations on how to extend SRTP with new
+ transforms are given in Section 6.
+
+4.1. Encryption
+
+ The following parameters are common to both pre-defined, non-NULL,
+ encryption transforms specified in this section.
+
+ * BLOCK_CIPHER-MODE indicates the block cipher used and its mode of
+ operation
+ * n_b is the bit-size of the block for the block cipher
+ * k_e is the session encryption key
+ * n_e is the bit-length of k_e
+ * k_s is the session salting key
+ * n_s is the bit-length of k_s
+ * SRTP_PREFIX_LENGTH is the octet length of the keystream prefix, a
+ non-negative integer, specified by the message authentication code
+ in use.
+
+ The distinct session keys and salts for SRTP/SRTCP are by default
+ derived as specified in Section 4.3.
+
+ The encryption transforms defined in SRTP map the SRTP packet index
+ and secret key into a pseudo-random keystream segment. Each
+ keystream segment encrypts a single RTP packet. The process of
+ encrypting a packet consists of generating the keystream segment
+ corresponding to the packet, and then bitwise exclusive-oring that
+ keystream segment onto the payload of the RTP packet to produce the
+ Encrypted Portion of the SRTP packet. In case the payload size is
+ not an integer multiple of n_b bits, the excess (least significant)
+ bits of the keystream are simply discarded. Decryption is done the
+ same way, but swapping the roles of the plaintext and ciphertext.
+
+
+
+Baugher, et al. Standards Track [Page 19]
+
+RFC 3711 SRTP March 2004
+
+
+ +----+ +------------------+---------------------------------+
+ | KG |-->| Keystream Prefix | Keystream Suffix |---+
+ +----+ +------------------+---------------------------------+ |
+ |
+ +---------------------------------+ v
+ | Payload of RTP Packet |->(*)
+ +---------------------------------+ |
+ |
+ +---------------------------------+ |
+ | Encrypted Portion of SRTP Packet|<--+
+ +---------------------------------+
+
+ Figure 3: Default SRTP Encryption Processing. Here KG denotes the
+ keystream generator, and (*) denotes bitwise exclusive-or.
+
+ The definition of how the keystream is generated, given the index,
+ depends on the cipher and its mode of operation. Below, two such
+ keystream generators are defined. The NULL cipher is also defined,
+ to be used when encryption of RTP is not required.
+
+ The SRTP definition of the keystream is illustrated in Figure 3. The
+ initial octets of each keystream segment MAY be reserved for use in a
+ message authentication code, in which case the keystream used for
+ encryption starts immediately after the last reserved octet. The
+ initial reserved octets are called the "keystream prefix" (not to be
+ confused with the "encryption prefix" of [RFC3550, Section 6.1]), and
+ the remaining octets are called the "keystream suffix". The
+ keystream prefix MUST NOT be used for encryption. The process is
+ illustrated in Figure 3.
+
+ The number of octets in the keystream prefix is denoted as
+ SRTP_PREFIX_LENGTH. The keystream prefix is indicated by a positive,
+ non-zero value of SRTP_PREFIX_LENGTH. This means that, even if
+ confidentiality is not to be provided, the keystream generator output
+ may still need to be computed for packet authentication, in which
+ case the default keystream generator (mode) SHALL be used.
+
+ The default cipher is the Advanced Encryption Standard (AES) [AES],
+ and we define two modes of running AES, (1) Segmented Integer Counter
+ Mode AES and (2) AES in f8-mode. In the remainder of this section,
+ let E(k,x) be AES applied to key k and input block x.
+
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 20]
+
+RFC 3711 SRTP March 2004
+
+
+4.1.1. AES in Counter Mode
+
+ Conceptually, counter mode [AES-CTR] consists of encrypting
+ successive integers. The actual definition is somewhat more
+ complicated, in order to randomize the starting point of the integer
+ sequence. Each packet is encrypted with a distinct keystream
+ segment, which SHALL be computed as follows.
+
+ A keystream segment SHALL be the concatenation of the 128-bit output
+ blocks of the AES cipher in the encrypt direction, using key k = k_e,
+ in which the block indices are in increasing order. Symbolically,
+ each keystream segment looks like
+
+ E(k, IV) || E(k, IV + 1 mod 2^128) || E(k, IV + 2 mod 2^128) ...
+
+ where the 128-bit integer value IV SHALL be defined by the SSRC, the
+ SRTP packet index i, and the SRTP session salting key k_s, as below.
+
+ IV = (k_s * 2^16) XOR (SSRC * 2^64) XOR (i * 2^16)
+
+ Each of the three terms in the XOR-sum above is padded with as many
+ leading zeros as needed to make the operation well-defined,
+ considered as a 128-bit value.
+
+ The inclusion of the SSRC allows the use of the same key to protect
+ distinct SRTP streams within the same RTP session, see the security
+ caveats in Section 9.1.
+
+ In the case of SRTCP, the SSRC of the first header of the compound
+ packet MUST be used, i SHALL be the 31-bit SRTCP index and k_e, k_s
+ SHALL be replaced by the SRTCP encryption session key and salt.
+
+ Note that the initial value, IV, is fixed for each packet and is
+ formed by "reserving" 16 zeros in the least significant bits for the
+ purpose of the counter. The number of blocks of keystream generated
+ for any fixed value of IV MUST NOT exceed 2^16 to avoid keystream
+ re-use, see below. The AES has a block size of 128 bits, so 2^16
+ output blocks are sufficient to generate the 2^23 bits of keystream
+ needed to encrypt the largest possible RTP packet (except for IPv6
+ "jumbograms" [RFC2675], which are not likely to be used for RTP-based
+ multimedia traffic). This restriction on the maximum bit-size of the
+ packet that can be encrypted ensures the security of the encryption
+ method by limiting the effectiveness of probabilistic attacks [BDJR].
+
+ For a particular Counter Mode key, each IV value used as an input
+ MUST be distinct, in order to avoid the security exposure of a two-
+ time pad situation (Section 9.1). To satisfy this constraint, an
+ implementation MUST ensure that the combination of the SRTP packet
+
+
+
+Baugher, et al. Standards Track [Page 21]
+
+RFC 3711 SRTP March 2004
+
+
+ index of ROC || SEQ, and the SSRC used in the construction of the IV
+ are distinct for any particular key. The failure to ensure this
+ uniqueness could be catastrophic for Secure RTP. This is in contrast
+ to the situation for RTP itself, which may be able to tolerate such
+ failures. It is RECOMMENDED that, if a dedicated security module is
+ present, the RTP sequence numbers and SSRC either be generated or
+ checked by that module (i.e., sequence-number and SSRC processing in
+ an SRTP system needs to be protected as well as the key).
+
+4.1.2. AES in f8-mode
+
+ To encrypt UMTS (Universal Mobile Telecommunications System, as 3G
+ networks) data, a solution (see [f8-a] [f8-b]) known as the f8-
+ algorithm has been developed. On a high level, the proposed scheme
+ is a variant of Output Feedback Mode (OFB) [HAC], with a more
+ elaborate initialization and feedback function. As in normal OFB,
+ the core consists of a block cipher. We also define here the use of
+ AES as a block cipher to be used in what we shall call "f8-mode of
+ operation" RTP encryption. The AES f8-mode SHALL use the same
+ default sizes for session key and salt as AES counter mode.
+
+ Figure 4 shows the structure of block cipher, E, running in f8-mode.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 22]
+
+RFC 3711 SRTP March 2004
+
+
+ IV
+ |
+ v
+ +------+
+ | |
+ +--->| E |
+ | +------+
+ | |
+ m -> (*) +-----------+-------------+-- ... ------+
+ | IV' | | | |
+ | | j=1 -> (*) j=2 -> (*) ... j=L-1 ->(*)
+ | | | | |
+ | | +-> (*) +-> (*) ... +-> (*)
+ | | | | | | | |
+ | v | v | v | v
+ | +------+ | +------+ | +------+ | +------+
+ k_e ---+--->| E | | | E | | | E | | | E |
+ | | | | | | | | | | |
+ +------+ | +------+ | +------+ | +------+
+ | | | | | | |
+ +------+ +--------+ +-- ... ----+ |
+ | | | |
+ v v v v
+ S(0) S(1) S(2) . . . S(L-1)
+
+ Figure 4. f8-mode of operation (asterisk, (*), denotes bitwise XOR).
+ The figure represents the KG in Figure 3, when AES-f8 is used.
+
+4.1.2.1. f8 Keystream Generation
+
+ The Initialization Vector (IV) SHALL be determined as described in
+ Section 4.1.2.2 (and in Section 4.1.2.3 for SRTCP).
+
+ Let IV', S(j), and m denote n_b-bit blocks. The keystream,
+ S(0) ||... || S(L-1), for an N-bit message SHALL be defined by
+ setting IV' = E(k_e XOR m, IV), and S(-1) = 00..0. For
+ j = 0,1,..,L-1 where L = N/n_b (rounded up to nearest integer if it
+ is not already an integer) compute
+
+ S(j) = E(k_e, IV' XOR j XOR S(j-1))
+
+ Notice that the IV is not used directly. Instead it is fed through E
+ under another key to produce an internal, "masked" value (denoted
+ IV') to prevent an attacker from gaining known input/output pairs.
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 23]
+
+RFC 3711 SRTP March 2004
+
+
+ The role of the internal counter, j, is to prevent short keystream
+ cycles. The value of the key mask m SHALL be
+
+ m = k_s || 0x555..5,
+
+ i.e., the session salting key, appended by the binary pattern 0101..
+ to fill out the entire desired key size, n_e.
+
+ The sender SHOULD NOT generate more than 2^32 blocks, which is
+ sufficient to generate 2^39 bits of keystream. Unlike counter mode,
+ there is no absolute threshold above (below) which f8 is guaranteed
+ to be insecure (secure). The above bound has been chosen to limit,
+ with sufficient security margin, the probability of degenerative
+ behavior in the f8 keystream generation.
+
+4.1.2.2. f8 SRTP IV Formation
+
+ The purpose of the following IV formation is to provide a feature
+ which we call implicit header authentication (IHA), see Section 9.5.
+
+ The SRTP IV for 128-bit block AES-f8 SHALL be formed in the following
+ way:
+
+ IV = 0x00 || M || PT || SEQ || TS || SSRC || ROC
+
+ M, PT, SEQ, TS, SSRC SHALL be taken from the RTP header; ROC is from
+ the cryptographic context.
+
+ The presence of the SSRC as part of the IV allows AES-f8 to be used
+ when a master key is shared between multiple streams within the same
+ RTP session, see Section 9.1.
+
+4.1.2.3. f8 SRTCP IV Formation
+
+ The SRTCP IV for 128-bit block AES-f8 SHALL be formed in the
+ following way:
+
+ IV= 0..0 || E || SRTCP index || V || P || RC || PT || length || SSRC
+
+ where V, P, RC, PT, length, SSRC SHALL be taken from the first header
+ in the RTCP compound packet. E and SRTCP index are the 1-bit and
+ 31-bit fields added to the packet.
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 24]
+
+RFC 3711 SRTP March 2004
+
+
+4.1.3. NULL Cipher
+
+ The NULL cipher is used when no confidentiality for RTP/RTCP is
+ requested. The keystream can be thought of as "000..0", i.e., the
+ encryption SHALL simply copy the plaintext input into the ciphertext
+ output.
+
+4.2. Message Authentication and Integrity
+
+ Throughout this section, M will denote data to be integrity
+ protected. In the case of SRTP, M SHALL consist of the Authenticated
+ Portion of the packet (as specified in Figure 1) concatenated with
+ the ROC, M = Authenticated Portion || ROC; in the case of SRTCP, M
+ SHALL consist of the Authenticated Portion (as specified in Figure 2)
+ only.
+
+ Common parameters:
+
+ * AUTH_ALG is the authentication algorithm
+ * k_a is the session message authentication key
+ * n_a is the bit-length of the authentication key
+ * n_tag is the bit-length of the output authentication tag
+ * SRTP_PREFIX_LENGTH is the octet length of the keystream prefix as
+ defined above, a parameter of AUTH_ALG
+
+ The distinct session authentication keys for SRTP/SRTCP are by
+ default derived as specified in Section 4.3.
+
+ The values of n_a, n_tag, and SRTP_PREFIX_LENGTH MUST be fixed for
+ any particular fixed value of the key.
+
+ We describe the process of computing authentication tags as follows.
+ The sender computes the tag of M and appends it to the packet. The
+ SRTP receiver verifies a message/authentication tag pair by computing
+ a new authentication tag over M using the selected algorithm and key,
+ and then compares it to the tag associated with the received message.
+ If the two tags are equal, then the message/tag pair is valid;
+ otherwise, it is invalid and the error audit message "AUTHENTICATION
+ FAILURE" MUST be returned.
+
+4.2.1. HMAC-SHA1
+
+ The pre-defined authentication transform for SRTP is HMAC-SHA1
+ [RFC2104]. With HMAC-SHA1, the SRTP_PREFIX_LENGTH (Figure 3) SHALL
+ be 0. For SRTP (respectively SRTCP), the HMAC SHALL be applied to
+ the session authentication key and M as specified above, i.e.,
+ HMAC(k_a, M). The HMAC output SHALL then be truncated to the n_tag
+ left-most bits.
+
+
+
+Baugher, et al. Standards Track [Page 25]
+
+RFC 3711 SRTP March 2004
+
+
+4.3. Key Derivation
+
+4.3.1. Key Derivation Algorithm
+
+ Regardless of the encryption or message authentication transform that
+ is employed (it may be an SRTP pre-defined transform or newly
+ introduced according to Section 6), interoperable SRTP
+ implementations MUST use the SRTP key derivation to generate session
+ keys. Once the key derivation rate is properly signaled at the start
+ of the session, there is no need for extra communication between the
+ parties that use SRTP key derivation.
+
+ packet index ---+
+ |
+ v
+ +-----------+ master +--------+ session encr_key
+ | ext | key | |---------->
+ | key mgmt |-------->| key | session auth_key
+ | (optional | | deriv |---------->
+ | rekey) |-------->| | session salt_key
+ | | master | |---------->
+ +-----------+ salt +--------+
+
+ Figure 5: SRTP key derivation.
+
+ At least one initial key derivation SHALL be performed by SRTP, i.e.,
+ the first key derivation is REQUIRED. Further applications of the
+ key derivation MAY be performed, according to the
+ "key_derivation_rate" value in the cryptographic context. The key
+ derivation function SHALL initially be invoked before the first
+ packet and then, when r > 0, a key derivation is performed whenever
+ index mod r equals zero. This can be thought of as "refreshing" the
+ session keys. The value of "key_derivation_rate" MUST be kept fixed
+ for the lifetime of the associated master key.
+
+ Interoperable SRTP implementations MAY also derive session salting
+ keys for encryption transforms, as is done in both of the pre-
+ defined transforms.
+
+ Let m and n be positive integers. A pseudo-random function family is
+ a set of keyed functions {PRF_n(k,x)} such that for the (secret)
+ random key k, given m-bit x, PRF_n(k,x) is an n-bit string,
+ computationally indistinguishable from random n-bit strings, see
+ [HAC]. For the purpose of key derivation in SRTP, a secure PRF with
+ m = 128 (or more) MUST be used, and a default PRF transform is
+ defined in Section 4.3.3.
+
+
+
+
+
+Baugher, et al. Standards Track [Page 26]
+
+RFC 3711 SRTP March 2004
+
+
+ Let "a DIV t" denote integer division of a by t, rounded down, and
+ with the convention that "a DIV 0 = 0" for all a. We also make the
+ convention of treating "a DIV t" as a bit string of the same length
+ as a, and thus "a DIV t" will in general have leading zeros.
+
+ Key derivation SHALL be defined as follows in terms of <label>, an
+ 8-bit constant (see below), master_salt and key_derivation_rate, as
+ determined in the cryptographic context, and index, the packet index
+ (i.e., the 48-bit ROC || SEQ for SRTP):
+
+ * Let r = index DIV key_derivation_rate (with DIV as defined above).
+
+ * Let key_id = <label> || r.
+
+ * Let x = key_id XOR master_salt, where key_id and master_salt are
+ aligned so that their least significant bits agree (right-
+ alignment).
+
+ <label> MUST be unique for each type of key to be derived. We
+ currently define <label> 0x00 to 0x05 (see below), and future
+ extensions MAY specify new values in the range 0x06 to 0xff for other
+ purposes. The n-bit SRTP key (or salt) for this packet SHALL then be
+ derived from the master key, k_master as follows:
+
+ PRF_n(k_master, x).
+
+ (The PRF may internally specify additional formatting and padding of
+ x, see e.g., Section 4.3.3 for the default PRF.)
+
+ The session keys and salt SHALL now be derived using:
+
+ - k_e (SRTP encryption): <label> = 0x00, n = n_e.
+
+ - k_a (SRTP message authentication): <label> = 0x01, n = n_a.
+
+ - k_s (SRTP salting key): <label> = 0x02, n = n_s.
+
+ where n_e, n_s, and n_a are from the cryptographic context.
+
+ The master key and master salt MUST be random, but the master salt
+ MAY be public.
+
+ Note that for a key_derivation_rate of 0, the application of the key
+ derivation SHALL take place exactly once.
+
+ The definition of DIV above is purely for notational convenience.
+ For a non-zero t among the set of allowed key derivation rates, "a
+ DIV t" can be implemented as a right-shift by the base-2 logarithm of
+
+
+
+Baugher, et al. Standards Track [Page 27]
+
+RFC 3711 SRTP March 2004
+
+
+ t. The derivation operation is further facilitated if the rates are
+ chosen to be powers of 256, but that granularity was considered too
+ coarse to be a requirement of this specification.
+
+ The upper limit on the number of packets that can be secured using
+ the same master key (see Section 9.2) is independent of the key
+ derivation.
+
+4.3.2. SRTCP Key Derivation
+
+ SRTCP SHALL by default use the same master key (and master salt) as
+ SRTP. To do this securely, the following changes SHALL be done to
+ the definitions in Section 4.3.1 when applying session key derivation
+ for SRTCP.
+
+ Replace the SRTP index by the 32-bit quantity: 0 || SRTCP index
+ (i.e., excluding the E-bit, replacing it with a fixed 0-bit), and use
+ <label> = 0x03 for the SRTCP encryption key, <label> = 0x04 for the
+ SRTCP authentication key, and, <label> = 0x05 for the SRTCP salting
+ key.
+
+4.3.3. AES-CM PRF
+
+ The currently defined PRF, keyed by 128, 192, or 256 bit master key,
+ has input block size m = 128 and can produce n-bit outputs for n up
+ to 2^23. PRF_n(k_master,x) SHALL be AES in Counter Mode as described
+ in Section 4.1.1, applied to key k_master, and IV equal to (x*2^16),
+ and with the output keystream truncated to the n first (left-most)
+ bits. (Requiring n/128, rounded up, applications of AES.)
+
+5. Default and mandatory-to-implement Transforms
+
+ The default transforms also are mandatory-to-implement transforms in
+ SRTP. Of course, "mandatory-to-implement" does not imply
+ "mandatory-to-use". Table 1 summarizes the pre-defined transforms.
+ The default values below are valid for the pre-defined transforms.
+
+ mandatory-to-impl. optional default
+
+ encryption AES-CM, NULL AES-f8 AES-CM
+ message integrity HMAC-SHA1 - HMAC-SHA1
+ key derivation (PRF) AES-CM - AES-CM
+
+ Table 1: Mandatory-to-implement, optional and default transforms in
+ SRTP and SRTCP.
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 28]
+
+RFC 3711 SRTP March 2004
+
+
+5.1. Encryption: AES-CM and NULL
+
+ AES running in Segmented Integer Counter Mode, as defined in Section
+ 4.1.1, SHALL be the default encryption algorithm. The default key
+ lengths SHALL be 128-bit for the session encryption key (n_e). The
+ default session salt key-length (n_s) SHALL be 112 bits.
+
+ The NULL cipher SHALL also be mandatory-to-implement.
+
+5.2. Message Authentication/Integrity: HMAC-SHA1
+
+ HMAC-SHA1, as defined in Section 4.2.1, SHALL be the default message
+ authentication code. The default session authentication key-length
+ (n_a) SHALL be 160 bits, the default authentication tag length
+ (n_tag) SHALL be 80 bits, and the SRTP_PREFIX_LENGTH SHALL be zero
+ for HMAC-SHA1. In addition, for SRTCP, the pre-defined HMAC-SHA1
+ MUST NOT be applied with a value of n_tag, nor n_a, that are smaller
+ than these defaults. For SRTP, smaller values are NOT RECOMMENDED,
+ but MAY be used after careful consideration of the issues in Section
+ 7.5 and 9.5.
+
+5.3. Key Derivation: AES-CM PRF
+
+ The AES Counter Mode based key derivation and PRF defined in Sections
+ 4.3.1 to 4.3.3, using a 128-bit master key, SHALL be the default
+ method for generating session keys. The default master salt length
+ SHALL be 112 bits and the default key-derivation rate SHALL be zero.
+
+6. Adding SRTP Transforms
+
+ Section 4 provides examples of the level of detail needed for
+ defining transforms. Whenever a new transform is to be added to
+ SRTP, a companion standard track RFC MUST be written to exactly
+ define how the new transform can be used with SRTP (and SRTCP). Such
+ a companion RFC SHOULD avoid overlap with the SRTP protocol document.
+ Note however, that it MAY be necessary to extend the SRTP or SRTCP
+ cryptographic context definition with new parameters (including fixed
+ or default values), add steps to the packet processing, or even add
+ fields to the SRTP/SRTCP packets. The companion RFC SHALL explain
+ any known issues regarding interactions between the transform and
+ other aspects of SRTP.
+
+ Each new transform document SHOULD specify its key attributes, e.g.,
+ size of keys (minimum, maximum, recommended), format of keys,
+ recommended/required processing of input keying material,
+ requirements/recommendations on key lifetime, re-keying and key
+ derivation, whether sharing of keys between SRTP and SRTCP is allowed
+ or not, etc.
+
+
+
+Baugher, et al. Standards Track [Page 29]
+
+RFC 3711 SRTP March 2004
+
+
+ An added message integrity transform SHOULD define a minimum
+ acceptable key/tag size for SRTCP, equivalent in strength to the
+ minimum values as defined in Section 5.2.
+
+7. Rationale
+
+ This section explains the rationale behind several important features
+ of SRTP.
+
+7.1. Key derivation
+
+ Key derivation reduces the burden on the key establishment. As many
+ as six different keys are needed per crypto context (SRTP and SRTCP
+ encryption keys and salts, SRTP and SRTCP authentication keys), but
+ these are derived from a single master key in a cryptographically
+ secure way. Thus, the key management protocol needs to exchange only
+ one master key (plus master salt when required), and then SRTP itself
+ derives all the necessary session keys (via the first, mandatory
+ application of the key derivation function).
+
+ Multiple applications of the key derivation function are optional,
+ but will give security benefits when enabled. They prevent an
+ attacker from obtaining large amounts of ciphertext produced by a
+ single fixed session key. If the attacker was able to collect a
+ large amount of ciphertext for a certain session key, he might be
+ helped in mounting certain attacks.
+
+ Multiple applications of the key derivation function provide
+ backwards and forward security in the sense that a compromised
+ session key does not compromise other session keys derived from the
+ same master key. This means that the attacker who is able to recover
+ a certain session key, is anyway not able to have access to messages
+ secured under previous and later session keys (derived from the same
+ master key). (Note that, of course, a leaked master key reveals all
+ the session keys derived from it.)
+
+ Considerations arise with high-rate key refresh, especially in large
+ multicast settings, see Section 11.
+
+7.2. Salting key
+
+ The master salt guarantees security against off-line key-collision
+ attacks on the key derivation that might otherwise reduce the
+ effective key size [MF00].
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 30]
+
+RFC 3711 SRTP March 2004
+
+
+ The derived session salting key used in the encryption, has been
+ introduced to protect against some attacks on additive stream
+ ciphers, see Section 9.2. The explicit inclusion method of the salt
+ in the IV has been selected for ease of hardware implementation.
+
+7.3. Message Integrity from Universal Hashing
+
+ The particular definition of the keystream given in Section 4.1 (the
+ keystream prefix) is to give provision for particular universal hash
+ functions, suitable for message authentication in the Wegman-Carter
+ paradigm [WC81]. Such functions are provably secure, simple, quick,
+ and especially appropriate for Digital Signal Processors and other
+ processors with a fast multiply operation.
+
+ No authentication transforms are currently provided in SRTP other
+ than HMAC-SHA1. Future transforms, like the above mentioned
+ universal hash functions, MAY be added following the guidelines in
+ Section 6.
+
+7.4. Data Origin Authentication Considerations
+
+ Note that in pair-wise communications, integrity and data origin
+ authentication are provided together. However, in group scenarios
+ where the keys are shared between members, the MAC tag only proves
+ that a member of the group sent the packet, but does not prevent
+ against a member impersonating another. Data origin authentication
+ (DOA) for multicast and group RTP sessions is a hard problem that
+ needs a solution; while some promising proposals are being
+ investigated [PCST1] [PCST2], more work is needed to rigorously
+ specify these technologies. Thus SRTP data origin authentication in
+ groups is for further study.
+
+ DOA can be done otherwise using signatures. However, this has high
+ impact in terms of bandwidth and processing time, therefore we do not
+ offer this form of authentication in the pre-defined packet-integrity
+ transform.
+
+ The presence of mixers and translators does not allow data origin
+ authentication in case the RTP payload and/or the RTP header are
+ manipulated. Note that these types of middle entities also disrupt
+ end-to-end confidentiality (as the IV formation depends e.g., on the
+ RTP header preservation). A certain trust model may choose to trust
+ the mixers/translators to decrypt/re-encrypt the media (this would
+ imply breaking the end-to-end security, with related security
+ implications).
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 31]
+
+RFC 3711 SRTP March 2004
+
+
+7.5. Short and Zero-length Message Authentication
+
+ As shown in Figure 1, the authentication tag is RECOMMENDED in SRTP.
+ A full 80-bit authentication-tag SHOULD be used, but a shorter tag or
+ even a zero-length tag (i.e., no message authentication) MAY be used
+ under certain conditions to support either of the following two
+ application environments.
+
+ 1. Strong authentication can be impractical in environments where
+ bandwidth preservation is imperative. An important special
+ case is wireless communication systems, in which bandwidth is a
+ scarce and expensive resource. Studies have shown that for
+ certain applications and link technologies, additional bytes
+ may result in a significant decrease in spectrum efficiency
+ [SWO]. Considerable effort has been made to design IP header
+ compression techniques to improve spectrum efficiency
+ [RFC3095]. A typical voice application produces 20 byte
+ samples, and the RTP, UDP and IP headers need to be jointly
+ compressed to one or two bytes on average in order to obtain
+ acceptable wireless bandwidth economy [RFC3095]. In this case,
+ strong authentication would impose nearly fifty percent
+ overhead.
+
+ 2. Authentication is impractical for applications that use data
+ links with fixed-width fields that cannot accommodate the
+ expansion due to the authentication tag. This is the case for
+ some important existing wireless channels. For example, zero-
+ byte header compression is used to adapt EVRC/SMV voice with
+ the legacy IS-95 bearer channel in CDMA2000 VoIP services. It
+ was found that not a single additional octet could be added to
+ the data, which motivated the creation of a zero-byte profile
+ for ROHC [RFC3242].
+
+ A short tag is secure for a restricted set of applications. Consider
+ a voice telephony application, for example, such as a G.729 audio
+ codec with a 20-millisecond packetization interval, protected by a
+ 32-bit message authentication tag. The likelihood of any given
+ packet being successfully forged is only one in 2^32. Thus an
+ adversary can control no more than 20 milliseconds of audio output
+ during a 994-day period, on average. In contrast, the effect of a
+ single forged packet can be much larger if the application is
+ stateful. A codec that uses relative or predictive compression
+ across packets will propagate the maliciously generated state,
+ affecting a longer duration of output.
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 32]
+
+RFC 3711 SRTP March 2004
+
+
+ Certainly not all SRTP or telephony applications meet the criteria
+ for short or zero-length authentication tags. Section 9.5.1
+ discusses the risks of weak or no message authentication, and section
+ 9.5 describes the circumstances when it is acceptable and when it is
+ unacceptable.
+
+8. Key Management Considerations
+
+ There are emerging key management standards [MIKEY] [KEYMGT] [SDMS]
+ for establishing an SRTP cryptographic context (e.g., an SRTP master
+ key). Both proprietary and open-standard key management methods are
+ likely to be used for telephony applications [MIKEY] [KINK] and
+ multicast applications [GDOI]. This section provides guidance for
+ key management systems that service SRTP session.
+
+ For initialization, an interoperable SRTP implementation SHOULD be
+ given the SSRC and MAY be given the initial RTP sequence number for
+ the RTP stream by key management (thus, key management has a
+ dependency on RTP operational parameters). Sending the RTP sequence
+ number in the key management may be useful e.g., when the initial
+ sequence number is close to wrapping (to avoid synchronization
+ problems), and to communicate the current sequence number to a
+ joining endpoint (to properly initialize its replay list).
+
+ If the pre-defined transforms are used, SRTP allows sharing of the
+ same master key between SRTP/SRTCP streams belonging to the same RTP
+ session.
+
+ First, sharing between SRTP streams belonging to the same RTP session
+ is secure if the design of the synchronization mechanism, i.e., the
+ IV, avoids keystream re-use (the two-time pad, Section 9.1). This is
+ taken care of by the fact that RTP provides for unique SSRCs for
+ streams belonging to the same RTP session. See Section 9.1 for
+ further discussion.
+
+ Second, sharing between SRTP and the corresponding SRTCP is secure.
+ The fact that an SRTP stream and its associated SRTCP stream both
+ carry the same SSRC does not constitute a problem for the two-time
+ pad due to the key derivation. Thus, SRTP and SRTCP corresponding to
+ one RTP session MAY share master keys (as they do by default).
+
+ Note that message authentication also has a dependency on SSRC
+ uniqueness that is unrelated to the problem of keystream reuse: SRTP
+ streams authenticated under the same key MUST have a distinct SSRC in
+ order to identify the sender of the message. This requirement is
+ needed because the SSRC is the cryptographically authenticated field
+
+
+
+
+
+Baugher, et al. Standards Track [Page 33]
+
+RFC 3711 SRTP March 2004
+
+
+ used to distinguish between different SRTP streams. Were two streams
+ to use identical SSRC values, then an adversary could substitute
+ messages from one stream into the other without detection.
+
+ SRTP/SRTCP MUST NOT share master keys under any other circumstances
+ than the ones given above, i.e., between SRTP and its corresponding
+ SRTCP, and, between streams belonging to the same RTP session.
+
+8.1. Re-keying
+
+ The recommended way for a particular key management system to provide
+ re-key within SRTP is by associating a master key in a crypto context
+ with an MKI.
+
+ This provides for easy master key retrieval (see Scenarios in Section
+ 11), but has the disadvantage of adding extra bits to each packet.
+ As noted in Section 7.5, some wireless links do not cater for added
+ bits, therefore SRTP also defines a more economic way of triggering
+ re-keying, via use of <From, To>, which works in some specific,
+ simple scenarios (see Section 8.1.1).
+
+ SRTP senders SHALL count the amount of SRTP and SRTCP traffic being
+ used for a master key and invoke key management to re-key if needed
+ (Section 9.2). These interactions are defined by the key management
+ interface to SRTP and are not defined by this protocol specification.
+
+8.1.1. Use of the <From, To> for re-keying
+
+ In addition to the use of the MKI, SRTP defines another optional
+ mechanism for master key retrieval, the <From, To>. The <From, To>
+ specifies the range of SRTP indices (a pair of sequence number and
+ ROC) within which a certain master key is valid, and is (when used)
+ part of the crypto context. By looking at the 48-bit SRTP index of
+ the current SRTP packet, the corresponding master key can be found by
+ determining which From-To interval it belongs to. For SRTCP, the
+ most recently observed/used SRTP index (which can be obtained from
+ the cryptographic context) is used for this purpose, even though
+ SRTCP has its own (31-bit) index (see caveat below).
+
+ This method, compared to the MKI, has the advantage of identifying
+ the master key and defining its lifetime without adding extra bits to
+ each packet. This could be useful, as already noted, for some
+ wireless links that do not cater for added bits. However, its use
+ SHOULD be limited to specific, very simple scenarios. We recommend
+ to limit its use when the RTP session is a simple unidirectional or
+ bi-directional stream. This is because in case of multiple streams,
+ it is difficult to trigger the re-key based on the <From, To> of a
+ single RTP stream. For example, if several streams share a master
+
+
+
+Baugher, et al. Standards Track [Page 34]
+
+RFC 3711 SRTP March 2004
+
+
+ key, there is no simple one-to-one correspondence between the index
+ sequence space of a certain stream, and the index sequence space on
+ which the <From, To> values are based. Consequently, when a master
+ key is shared between streams, one of these streams MUST be
+ designated by key management as the one whose index space defines the
+ re-keying points. Also, the re-key triggering on SRTCP is based on
+ the correspondent SRTP stream, i.e., when the SRTP stream changes the
+ master key, so does the correspondent SRTCP. This becomes obviously
+ more and more complex with multiple streams.
+
+ The default values for the <From, To> are "from the first observed
+ packet" and "until further notice". However, the maximum limit of
+ SRTP/SRTCP packets that are sent under each given master/session key
+ (Section 9.2) MUST NOT be exceeded.
+
+ In case the <From, To> is used as key retrieval, then the MKI is not
+ inserted in the packet (and its indicator in the crypto context is
+ zero). However, using the MKI does not exclude using <From, To> key
+ lifetime simultaneously. This can for instance be useful to signal
+ at the sender side at which point in time an MKI is to be made
+ active.
+
+8.2. Key Management parameters
+
+ The table below lists all SRTP parameters that key management can
+ supply. For reference, it also provides a summary of the default and
+ mandatory-to-support values for an SRTP implementation as described
+ in Section 5.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 35]
+
+RFC 3711 SRTP March 2004
+
+
+ Parameter Mandatory-to-support Default
+ --------- -------------------- -------
+
+ SRTP and SRTCP encr transf. AES_CM, NULL AES_CM
+ (Other possible values: AES_f8)
+
+ SRTP and SRTCP auth transf. HMAC-SHA1 HMAC-SHA1
+
+ SRTP and SRTCP auth params:
+ n_tag (tag length) 80 80
+ SRTP prefix_length 0 0
+
+ Key derivation PRF AES_CM AES_CM
+
+ Key material params
+ (for each master key):
+ master key length 128 128
+ n_e (encr session key length) 128 128
+ n_a (auth session key length) 160 160
+ master salt key
+ length of the master salt 112 112
+ n_s (session salt key length) 112 112
+ key derivation rate 0 0
+
+ key lifetime
+ SRTP-packets-max-lifetime 2^48 2^48
+ SRTCP-packets-max-lifetime 2^31 2^31
+ from-to-lifetime <From, To>
+ MKI indicator 0 0
+ length of the MKI 0 0
+ value of the MKI
+
+ Crypto context index params:
+ SSRC value
+ ROC
+ SEQ
+ SRTCP Index
+ Transport address
+ Port number
+
+ Relation to other RTP profiles:
+ sender's order between FEC and SRTP FEC-SRTP FEC-SRTP
+ (see Section 10)
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 36]
+
+RFC 3711 SRTP March 2004
+
+
+9. Security Considerations
+
+9.1. SSRC collision and two-time pad
+
+ Any fixed keystream output, generated from the same key and index
+ MUST only be used to encrypt once. Re-using such keystream (jokingly
+ called a "two-time pad" system by cryptographers), can seriously
+ compromise security. The NSA's VENONA project [C99] provides a
+ historical example of such a compromise. It is REQUIRED that
+ automatic key management be used for establishing and maintaining
+ SRTP and SRTCP keying material; this requirement is to avoid
+ keystream reuse, which is more likely to occur with manual key
+ management. Furthermore, in SRTP, a "two-time pad" is avoided by
+ requiring the key, or some other parameter of cryptographic
+ significance, to be unique per RTP/RTCP stream and packet. The pre-
+ defined SRTP transforms accomplish packet-uniqueness by including the
+ packet index and stream-uniqueness by inclusion of the SSRC.
+
+ The pre-defined transforms (AES-CM and AES-f8) allow master keys to
+ be shared across streams belonging to the same RTP session by the
+ inclusion of the SSRC in the IV. A master key MUST NOT be shared
+ among different RTP sessions.
+
+ Thus, the SSRC MUST be unique between all the RTP streams within the
+ same RTP session that share the same master key. RTP itself provides
+ an algorithm for detecting SSRC collisions within the same RTP
+ session. Thus, temporary collisions could lead to temporary two-time
+ pad, in the unfortunate event that SSRCs collide at a point in time
+ when the streams also have identical sequence numbers (occurring with
+ probability roughly 2^(-48)). Therefore, the key management SHOULD
+ take care of avoiding such SSRC collisions by including the SSRCs to
+ be used in the session as negotiation parameters, proactively
+ assuring their uniqueness. This is a strong requirements in
+ scenarios where for example, there are multiple senders that can
+ start to transmit simultaneously, before SSRC collision are detected
+ at the RTP level.
+
+ Note also that even with distinct SSRCs, extensive use of the same
+ key might improve chances of probabilistic collision and time-
+ memory-tradeoff attacks succeeding.
+
+ As described, master keys MAY be shared between streams belonging to
+ the same RTP session, but it is RECOMMENDED that each SSRC have its
+ own master key. When master keys are shared among SSRC participants
+ and SSRCs are managed by a key management module as recommended
+ above, the RECOMMENDED policy for an SSRC collision error is for the
+ participant to leave the SRTP session as it is a sign of malfunction.
+
+
+
+
+Baugher, et al. Standards Track [Page 37]
+
+RFC 3711 SRTP March 2004
+
+
+9.2. Key Usage
+
+ The effective key size is determined (upper bounded) by the size of
+ the master key and, for encryption, the size of the salting key. Any
+ additive stream cipher is vulnerable to attacks that use statistical
+ knowledge about the plaintext source to enable key collision and
+ time-memory tradeoff attacks [MF00] [H80] [BS00]. These attacks take
+ advantage of commonalities among plaintexts, and provide a way for a
+ cryptanalyst to amortize the computational effort of decryption over
+ many keys, or over many bytes of output, thus reducing the effective
+ key size of the cipher. A detailed analysis of these attacks and
+ their applicability to the encryption of Internet traffic is provided
+ in [MF00]. In summary, the effective key size of SRTP when used in a
+ security system in which m distinct keys are used, is equal to the
+ key size of the cipher less the logarithm (base two) of m.
+ Protection against such attacks can be provided simply by increasing
+ the size of the keys used, which here can be accomplished by the use
+ of the salting key. Note that the salting key MUST be random but MAY
+ be public. A salt size of (the suggested) size 112 bits protects
+ against attacks in scenarios where at most 2^112 keys are in use.
+ This is sufficient for all practical purposes.
+
+ Implementations SHOULD use keys that are as large as possible.
+ Please note that in many cases increasing the key size of a cipher
+ does not affect the throughput of that cipher.
+
+ The use of the SRTP and SRTCP indices in the pre-defined transforms
+ fixes the maximum number of packets that can be secured with the same
+ key. This limit is fixed to 2^48 SRTP packets for an SRTP stream,
+ and 2^31 SRTCP packets, when SRTP and SRTCP are considered
+ independently. Due to for example re-keying, reaching this limit may
+ or may not coincide with wrapping of the indices, and thus the sender
+ MUST keep packet counts. However, when the session keys for related
+ SRTP and SRTCP streams are derived from the same master key (the
+ default behavior, Section 4.3), the upper bound that has to be
+ considered is in practice the minimum of the two quantities. That
+ is, when 2^48 SRTP packets or 2^31 SRTCP packets have been secured
+ with the same key (whichever occurs before), the key management MUST
+ be called to provide new master key(s) (previously stored and used
+ keys MUST NOT be used again), or the session MUST be terminated. If
+ a sender of RTCP discovers that the sender of SRTP (or SRTCP) has not
+ updated the master or session key prior to sending 2^48 SRTP (or 2^31
+ SRTCP) packets belonging to the same SRTP (SRTCP) stream, it is up to
+ the security policy of the RTCP sender how to behave, e.g., whether
+ an RTCP BYE-packet should be sent and/or if the event should be
+ logged.
+
+
+
+
+
+Baugher, et al. Standards Track [Page 38]
+
+RFC 3711 SRTP March 2004
+
+
+ Note: in most typical applications (assuming at least one RTCP packet
+ for every 128,000 RTP packets), it will be the SRTCP index that first
+ reaches the upper limit, although the time until this occurs is very
+ long: even at 200 SRTCP packets/sec, the 2^31 index space of SRTCP is
+ enough to secure approximately 4 months of communication.
+
+ Note that if the master key is to be shared between SRTP streams
+ within the same RTP session (Section 9.1), although the above bounds
+ are on a per stream (i.e., per SSRC) basis, the sender MUST base re-
+ key decision on the stream whose sequence number space is the first
+ to be exhausted.
+
+ Key derivation limits the amount of plaintext that is encrypted with
+ a fixed session key, and made available to an attacker for analysis,
+ but key derivation does not extend the master key's lifetime. To see
+ this, simply consider our requirements to avoid two-time pad: two
+ distinct packets MUST either be processed with distinct IVs, or with
+ distinct session keys, and both the distinctness of IV and of the
+ session keys are (for the pre-defined transforms) dependent on the
+ distinctness of the packet indices.
+
+ Note that with the key derivation, the effective key size is at most
+ that of the master key, even if the derived session key is
+ considerably longer. With the pre-defined authentication transform,
+ the session authentication key is 160 bits, but the master key by
+ default is only 128 bits. This design choice was made to comply with
+ certain recommendations in [RFC2104] so that an existing HMAC
+ implementation can be plugged into SRTP without problems. Since the
+ default tag size is 80 bits, it is, for the applications in mind,
+ also considered acceptable from security point of view. Users having
+ concerns about this are RECOMMENDED to instead use a 192 bit master
+ key in the key derivation. It was, however, chosen not to mandate
+ 192-bit keys since existing AES implementations to be used in the
+ key-derivation may not always support key-lengths other than 128
+ bits. Since AES is not defined (or properly analyzed) for use with
+ 160 bit keys it is NOT RECOMMENDED that ad-hoc key-padding schemes
+ are used to pad shorter keys to 192 or 256 bits.
+
+9.3. Confidentiality of the RTP Payload
+
+ SRTP's pre-defined ciphers are "seekable" stream ciphers, i.e.,
+ ciphers able to efficiently seek to arbitrary locations in their
+ keystream (so that the encryption or decryption of one packet does
+ not depend on preceding packets). By using seekable stream ciphers,
+ SRTP avoids the denial of service attacks that are possible on stream
+ ciphers that lack this property. It is important to be aware that,
+ as with any stream cipher, the exact length of the payload is
+ revealed by the encryption. This means that it may be possible to
+
+
+
+Baugher, et al. Standards Track [Page 39]
+
+RFC 3711 SRTP March 2004
+
+
+ deduce certain "formatting bits" of the payload, as the length of the
+ codec output might vary due to certain parameter settings etc. This,
+ in turn, implies that the corresponding bit of the keystream can be
+ deduced. However, if the stream cipher is secure (counter mode and
+ f8 are provably secure under certain assumptions [BDJR] [KSYH] [IK]),
+ knowledge of a few bits of the keystream will not aid an attacker in
+ predicting subsequent keystream bits. Thus, the payload length (and
+ information deducible from this) will leak, but nothing else.
+
+ As some RTP packet could contain highly predictable data, e.g., SID,
+ it is important to use a cipher designed to resist known plaintext
+ attacks (which is the current practice).
+
+9.4. Confidentiality of the RTP Header
+
+ In SRTP, RTP headers are sent in the clear to allow for header
+ compression. This means that data such as payload type,
+ synchronization source identifier, and timestamp are available to an
+ eavesdropper. Moreover, since RTP allows for future extensions of
+ headers, we cannot foresee what kind of possibly sensitive
+ information might also be "leaked".
+
+ SRTP is a low-cost method, which allows header compression to reduce
+ bandwidth. It is up to the endpoints' policies to decide about the
+ security protocol to employ. If one really needs to protect headers,
+ and is allowed to do so by the surrounding environment, then one
+ should also look at alternatives, e.g., IPsec [RFC2401].
+
+9.5. Integrity of the RTP payload and header
+
+ SRTP messages are subject to attacks on their integrity and source
+ identification, and these risks are discussed in Section 9.5.1. To
+ protect against these attacks, each SRTP stream SHOULD be protected
+ by HMAC-SHA1 [RFC2104] with an 80-bit output tag and a 160-bit key,
+ or a message authentication code with equivalent strength. Secure
+ RTP SHOULD NOT be used without message authentication, except under
+ the circumstances described in this section. It is important to note
+ that encryption algorithms, including AES Counter Mode and f8, do not
+ provide message authentication. SRTCP MUST NOT be used with weak (or
+ NULL) authentication.
+
+ SRTP MAY be used with weak authentication (e.g., a 32-bit
+ authentication tag), or with no authentication (the NULL
+ authentication algorithm). These options allow SRTP to be used to
+ provide confidentiality in situations where
+
+ * weak or null authentication is an acceptable security risk, and
+ * it is impractical to provide strong message authentication.
+
+
+
+Baugher, et al. Standards Track [Page 40]
+
+RFC 3711 SRTP March 2004
+
+
+ These conditions are described below and in Section 7.5. Note that
+ both conditions MUST hold in order for weak or null authentication to
+ be used. The risks associated with exercising the weak or null
+ authentication options need to be considered by a security audit
+ prior to their use for a particular application or environment given
+ the risks, which are discussed in Section 9.5.1.
+
+ Weak authentication is acceptable when the RTP application is such
+ that the effect of a small fraction of successful forgeries is
+ negligible. If the application is stateless, then the effect of a
+ single forged RTP packet is limited to the decoding of that
+ particular packet. Under this condition, the size of the
+ authentication tag MUST ensure that only a negligible fraction of the
+ packets passed to the RTP application by the SRTP receiver can be
+ forgeries. This fraction is negligible when an adversary, if given
+ control of the forged packets, is not able to make a significant
+ impact on the output of the RTP application (see the example of
+ Section 7.5).
+
+ Weak or null authentication MAY be acceptable when it is unlikely
+ that an adversary can modify ciphertext so that it decrypts to an
+ intelligible value. One important case is when it is difficult for
+ an adversary to acquire the RTP plaintext data, since for many
+ codecs, an adversary that does not know the input signal cannot
+ manipulate the output signal in a controlled way. In many cases it
+ may be difficult for the adversary to determine the actual value of
+ the plaintext. For example, a hidden snooping device might be
+ required in order to know a live audio or video signal. The
+ adversary's signal must have a quality equivalent to or greater than
+ that of the signal under attack, since otherwise the adversary would
+ not have enough information to encode that signal with the codec used
+ by the victim. Plaintext prediction may also be especially difficult
+ for an interactive application such as a telephone call.
+
+ Weak or null authentication MUST NOT be used when the RTP application
+ makes data forwarding or access control decisions based on the RTP
+ data. In such a case, an attacker may be able to subvert
+ confidentiality by causing the receiver to forward data to an
+ attacker. See Section 3 of [B96] for a real-life example of such
+ attacks.
+
+ Null authentication MUST NOT be used when a replay attack, in which
+ an adversary stores packets then replays them later in the session,
+ could have a non-negligible impact on the receiver. An example of a
+ successful replay attack is the storing of the output of a
+ surveillance camera for a period of time, later followed by the
+
+
+
+
+
+Baugher, et al. Standards Track [Page 41]
+
+RFC 3711 SRTP March 2004
+
+
+ injection of that output to the monitoring station to avoid
+ surveillance. Encryption does not protect against this attack, and
+ non-null authentication is REQUIRED in order to defeat it.
+
+ If existential message forgery is an issue, i.e., when the accuracy
+ of the received data is of non-negligible importance, null
+ authentication MUST NOT be used.
+
+9.5.1. Risks of Weak or Null Message Authentication
+
+ During a security audit considering the use of weak or null
+ authentication, it is important to keep in mind the following attacks
+ which are possible when no message authentication algorithm is used.
+
+ An attacker who cannot predict the plaintext is still always able to
+ modify the message sent between the sender and the receiver so that
+ it decrypts to a random plaintext value, or to send a stream of bogus
+ packets to the receiver that will decrypt to random plaintext values.
+ This attack is essentially a denial of service attack, though in the
+ absence of message authentication, the RTP application will have
+ inputs that are bit-wise correlated with the true value. Some
+ multimedia codecs and common operating systems will crash when such
+ data are accepted as valid video data. This denial of service attack
+ may be a much larger threat than that due to an attacker dropping,
+ delaying, or re-ordering packets.
+
+ An attacker who cannot predict the plaintext can still replay a
+ previous message with certainty that the receiver will accept it.
+ Applications with stateless codecs might be robust against this type
+ of attack, but for other, more complex applications these attacks may
+ be far more grave.
+
+ An attacker who can predict the plaintext can modify the ciphertext
+ so that it will decrypt to any value of her choosing. With an
+ additive stream cipher, an attacker will always be able to change
+ individual bits.
+
+ An attacker may be able to subvert confidentiality due to the lack of
+ authentication when a data forwarding or access control decision is
+ made on decrypted but unauthenticated plaintext. This is because the
+ receiver may be fooled into forwarding data to an attacker, leading
+ to an indirect breach of confidentiality (see Section 3 of [B96]).
+ This is because data-forwarding decisions are made on the decrypted
+ plaintext; information in the plaintext will determine to what subnet
+ (or process) the plaintext is forwarded in ESP [RFC2401] tunnel mode
+ (respectively, transport mode). When Secure RTP is used without
+
+
+
+
+
+Baugher, et al. Standards Track [Page 42]
+
+RFC 3711 SRTP March 2004
+
+
+ message authentication, it should be verified that the application
+ does not make data forwarding or access control decisions based on
+ the decrypted plaintext.
+
+ Some cipher modes of operation that require padding, e.g., standard
+ cipher block chaining (CBC) are very sensitive to attacks on
+ confidentiality if certain padding types are used in the absence of
+ integrity. The attack [V02] shows that this is indeed the case for
+ the standard RTP padding as discussed in reference to Figure 1, when
+ used together with CBC mode. Later transform additions to SRTP MUST
+ therefore carefully consider the risk of using this padding without
+ proper integrity protection.
+
+9.5.2. Implicit Header Authentication
+
+ The IV formation of the f8-mode gives implicit authentication (IHA)
+ of the RTP header, even when message authentication is not used.
+ When IHA is used, an attacker that modifies the value of the RTP
+ header will cause the decryption process at the receiver to produce
+ random plaintext values. While this protection is not equivalent to
+ message authentication, it may be useful for some applications.
+
+10. Interaction with Forward Error Correction mechanisms
+
+ The default processing when using Forward Error Correction (e.g., RFC
+ 2733) processing with SRTP SHALL be to perform FEC processing prior
+ to SRTP processing on the sender side and to perform SRTP processing
+ prior to FEC processing on the receiver side. Any change to this
+ ordering (reversing it, or, placing FEC between SRTP encryption and
+ SRTP authentication) SHALL be signaled out of band.
+
+11. Scenarios
+
+ SRTP can be used as security protocol for the RTP/RTCP traffic in
+ many different scenarios. SRTP has a number of configuration
+ options, in particular regarding key usage, and can have impact on
+ the total performance of the application according to the way it is
+ used. Hence, the use of SRTP is dependent on the kind of scenario
+ and application it is used with. In the following, we briefly
+ illustrate some use cases for SRTP, and give some guidelines for
+ recommended setting of its options.
+
+11.1. Unicast
+
+ A typical example would be a voice call or video-on-demand
+ application.
+
+
+
+
+
+Baugher, et al. Standards Track [Page 43]
+
+RFC 3711 SRTP March 2004
+
+
+ Consider one bi-directional RTP stream, as one RTP session. It is
+ possible for the two parties to share the same master key in the two
+ directions according to the principles of Section 9.1. The first
+ round of the key derivation splits the master key into any or all of
+ the following session keys (according to the provided security
+ functions):
+
+ SRTP_encr_key, SRTP_auth_key, SRTCP_encr_key, and SRTCP_auth key.
+
+ (For simplicity, we omit discussion of the salts, which are also
+ derived.) In this scenario, it will in most cases suffice to have a
+ single master key with the default lifetime. This guarantees
+ sufficiently long lifetime of the keys and a minimum set of keys in
+ place for most practical purposes. Also, in this case RTCP
+ protection can be applied smoothly. Under these assumptions, use of
+ the MKI can be omitted. As the key-derivation in combination with
+ large difference in the packet rate in the respective directions may
+ require simultaneous storage of several session keys, if storage is
+ an issue, we recommended to use low-rate key derivation.
+
+ The same considerations can be extended to the unicast scenario with
+ multiple RTP sessions, where each session would have a distinct
+ master key.
+
+11.2. Multicast (one sender)
+
+ Just as with (unprotected) RTP, a scalability issue arises in big
+ groups due to the possibly very large amount of SRTCP Receiver
+ Reports that the sender might need to process. In SRTP, the sender
+ may have to keep state (the cryptographic context) for each receiver,
+ or more precisely, for the SRTCP used to protect Receiver Reports.
+ The overhead increases proportionally to the size of the group. In
+ particular, re-keying requires special concern, see below.
+
+ Consider first a small group of receivers. There are a few possible
+ setups with the distribution of master keys among the receivers.
+ Given a single RTP session, one possibility is that the receivers
+ share the same master key as per Section 9.1 to secure all their
+ respective RTCP traffic. This shared master key could then be the
+ same one used by the sender to protect its outbound SRTP traffic.
+ Alternatively, it could be a master key shared only among the
+ receivers and used solely for their SRTCP traffic. Both alternatives
+ require the receivers to trust each other.
+
+ Considering SRTCP and key storage, it is recommended to use low-rate
+ (or zero) key_derivation (except the mandatory initial one), so that
+ the sender does not need to store too many session keys (each SRTCP
+ stream might otherwise have a different session key at a given point
+
+
+
+Baugher, et al. Standards Track [Page 44]
+
+RFC 3711 SRTP March 2004
+
+
+ in time, as the SRTCP sources send at different times). Thus, in
+ case key derivation is wanted for SRTP, the cryptographic context for
+ SRTP can be kept separate from the SRTCP crypto context, so that it
+ is possible to have a key_derivation_rate of 0 for SRTCP and a non-
+ zero value for SRTP.
+
+ Use of the MKI for re-keying is RECOMMENDED for most applications
+ (see Section 8.1).
+
+ If there are more than one SRTP/SRTCP stream (within the same RTP
+ session) that share the master key, the upper limit of 2^48 SRTP
+ packets / 2^31 SRTCP packets means that, before one of the streams
+ reaches its maximum number of packets, re-keying MUST be triggered on
+ ALL streams sharing the master key. (From strict security point of
+ view, only the stream reaching the maximum would need to be re-keyed,
+ but then the streams would no longer be sharing master key, which is
+ the intention.) A local policy at the sender side should force
+ rekeying in a way that the maximum packet limit is not reached on any
+ of the streams. Use of the MKI for re-keying is RECOMMENDED.
+
+ In large multicast with one sender, the same considerations as for
+ the small group multicast hold. The biggest issue in this scenario
+ is the additional load placed at the sender side, due to the state
+ (cryptographic contexts) that has to be maintained for each receiver,
+ sending back RTCP Receiver Reports. At minimum, a replay window
+ might need to be maintained for each RTCP source.
+
+11.3. Re-keying and access control
+
+ Re-keying may occur due to access control (e.g., when a member is
+ removed during a multicast RTP session), or for pure cryptographic
+ reasons (e.g., the key is at the end of its lifetime). When using
+ SRTP default transforms, the master key MUST be replaced before any
+ of the index spaces are exhausted for any of the streams protected by
+ one and the same master key.
+
+ How key management re-keys SRTP implementations is out of scope, but
+ it is clear that there are straightforward ways to manage keys for a
+ multicast group. In one-sender multicast, for example, it is
+ typically the responsibility of the sender to determine when a new
+ key is needed. The sender is the one entity that can keep track of
+ when the maximum number of packets has been sent, as receivers may
+ join and leave the session at any time, there may be packet loss and
+ delay etc. In scenarios other than one-sender multicast, other
+ methods can be used. Here, one must take into consideration that key
+ exchange can be a costly operation, taking several seconds for a
+ single exchange. Hence, some time before the master key is
+ exhausted/expires, out-of-band key management is initiated, resulting
+
+
+
+Baugher, et al. Standards Track [Page 45]
+
+RFC 3711 SRTP March 2004
+
+
+ in a new master key that is shared with the receiver(s). In any
+ event, to maintain synchronization when switching to the new key,
+ group policy might choose between using the MKI and the <From, To>,
+ as described in Section 8.1.
+
+ For access control purposes, the <From, To> periods are set at the
+ desired granularity, dependent on the packet rate. High rate re-
+ keying can be problematic for SRTCP in some large-group scenarios.
+ As mentioned, there are potential problems in using the SRTP index,
+ rather than the SRTCP index, for determining the master key. In
+ particular, for short periods during switching of master keys, it may
+ be the case that SRTCP packets are not under the current master key
+ of the correspondent SRTP. Therefore, using the MKI for re-keying in
+ such scenarios will produce better results.
+
+11.4. Summary of basic scenarios
+
+ The description of these scenarios highlights some recommendations on
+ the use of SRTP, mainly related to re-keying and large scale
+ multicast:
+
+ - Do not use fast re-keying with the <From, To> feature. It may, in
+ particular, give problems in retrieving the correct SRTCP key, if
+ an SRTCP packet arrives close to the re-keying time. The MKI
+ SHOULD be used in this case.
+
+ - If multiple SRTP streams in the same RTP session share the same
+ master key, also moderate rate re-keying MAY have the same
+ problems, and the MKI SHOULD be used.
+
+ - Though offering increased security, a non-zero key_derivation_rate
+ is NOT RECOMMENDED when trying to minimize the number of keys in
+ use with multiple streams.
+
+12. IANA Considerations
+
+ The RTP specification establishes a registry of profile names for use
+ by higher-level control protocols, such as the Session Description
+ Protocol (SDP), to refer to transport methods. This profile
+ registers the name "RTP/SAVP".
+
+ SRTP uses cryptographic transforms which a key management protocol
+ signals. It is the task of each particular key management protocol
+ to register the cryptographic transforms or suites of transforms with
+ IANA. The key management protocol conveys these protocol numbers,
+ not SRTP, and each key management protocol chooses the numbering
+ scheme and syntax that it requires.
+
+
+
+
+Baugher, et al. Standards Track [Page 46]
+
+RFC 3711 SRTP March 2004
+
+
+ Specification of a key management protocol for SRTP is out of scope
+ here. Section 8.2, however, provides guidance on the parameters that
+ need to be defined for the default and mandatory transforms.
+
+13. Acknowledgements
+
+ David Oran (Cisco) and Rolf Blom (Ericsson) are co-authors of this
+ document but their valuable contributions are acknowledged here to
+ keep the length of the author list down.
+
+ The authors would in addition like to thank Magnus Westerlund, Brian
+ Weis, Ghyslain Pelletier, Morgan Lindqvist, Robert Fairlie-
+ Cuninghame, Adrian Perrig, the AVT WG and in particular the chairmen
+ Colin Perkins and Stephen Casner, the Transport and Security Area
+ Directors, and Eric Rescorla for their reviews and support.
+
+14. References
+
+14.1. Normative References
+
+ [AES] NIST, "Advanced Encryption Standard (AES)", FIPS PUB 197,
+ http://www.nist.gov/aes/
+
+ [RFC2104] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed-
+ Hashing for Message Authentication", RFC 2104, February
+ 1997.
+
+ [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
+ Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+ [RFC2401] Kent, S. and R. Atkinson, "Security Architecture for
+ Internet Protocol", RFC 2401, November 1998.
+
+ [RFC2828] Shirey, R., "Internet Security Glossary", FYI 36, RFC 2828,
+ May 2000.
+
+ [RFC3550] Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson,
+ "RTP: A Transport Protocol for Real-time Applications", RFC
+ 3550, July 2003.
+
+ [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
+ Video Conferences with Minimal Control", RFC 3551, July
+ 2003.
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 47]
+
+RFC 3711 SRTP March 2004
+
+
+14.2. Informative References
+
+ [AES-CTR] Lipmaa, H., Rogaway, P. and D. Wagner, "CTR-Mode
+ Encryption", NIST, http://csrc.nist.gov/encryption/modes/
+ workshop1/papers/lipmaa-ctr.pdf
+
+ [B96] Bellovin, S., "Problem Areas for the IP Security
+ Protocols," in Proceedings of the Sixth Usenix Unix
+ Security Symposium, pp. 1-16, San Jose, CA, July 1996
+ (http://www.research.att.com/~smb/papers/index.html).
+
+ [BDJR] Bellare, M., Desai, A., Jokipii, E. and P. Rogaway, "A
+ Concrete Treatment of Symmetric Encryption: Analysis of DES
+ Modes of Operation", Proceedings 38th IEEE FOCS, pp. 394-
+ 403, 1997.
+
+ [BS00] Biryukov, A. and A. Shamir, "Cryptanalytic Time/Memory/Data
+ Tradeoffs for Stream Ciphers", Proceedings, ASIACRYPT 2000,
+ LNCS 1976, pp. 1-13, Springer Verlag.
+
+ [C99] Crowell, W. P., "Introduction to the VENONA Project",
+ http://www.nsa.gov:8080/docs/venona/index.html.
+
+ [CTR] Dworkin, M., NIST Special Publication 800-38A,
+ "Recommendation for Block Cipher Modes of Operation:
+ Methods and Techniques", 2001.
+ http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-
+ 38a.pdf.
+
+ [f8-a] 3GPP TS 35.201 V4.1.0 (2001-12) Technical Specification 3rd
+ Generation Partnership Project; Technical Specification
+ Group Services and System Aspects; 3G Security;
+ Specification of the 3GPP Confidentiality and Integrity
+ Algorithms; Document 1: f8 and f9 Specification (Release
+ 4).
+
+ [f8-b] 3GPP TR 33.908 V4.0.0 (2001-09) Technical Report 3rd
+ Generation Partnership Project; Technical Specification
+ Group Services and System Aspects; 3G Security; General
+ Report on the Design, Specification and Evaluation of 3GPP
+ Standard Confidentiality and Integrity Algorithms (Release
+ 4).
+
+ [GDOI] Baugher, M., Weis, B., Hardjono, T. and H. Harney, "The
+ Group Domain of Interpretation, RFC 3547, July 2003.
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 48]
+
+RFC 3711 SRTP March 2004
+
+
+ [HAC] Menezes, A., Van Oorschot, P. and S. Vanstone, "Handbook
+ of Applied Cryptography", CRC Press, 1997, ISBN 0-8493-
+ 8523-7.
+
+ [H80] Hellman, M. E., "A cryptanalytic time-memory trade-off",
+ IEEE Transactions on Information Theory, July 1980, pp.
+ 401-406.
+
+ [IK] T. Iwata and T. Kohno: "New Security Proofs for the 3GPP
+ Confidentiality and Integrity Algorithms", Proceedings of
+ FSE 2004.
+
+ [KINK] Thomas, M. and J. Vilhuber, "Kerberized Internet
+ Negotiation of Keys (KINK)", Work in Progress.
+
+ [KEYMGT] Arrko, J., et al., "Key Management Extensions for Session
+ Description Protocol (SDP) and Real Time Streaming Protocol
+ (RTSP)", Work in Progress.
+
+ [KSYH] Kang, J-S., Shin, S-U., Hong, D. and O. Yi, "Provable
+ Security of KASUMI and 3GPP Encryption Mode f8",
+ Proceedings Asiacrypt 2001, Springer Verlag LNCS 2248, pp.
+ 255-271, 2001.
+
+ [MIKEY] Arrko, J., et. al., "MIKEY: Multimedia Internet KEYing",
+ Work in Progress.
+
+ [MF00] McGrew, D. and S. Fluhrer, "Attacks on Encryption of
+ Redundant Plaintext and Implications on Internet Security",
+ the Proceedings of the Seventh Annual Workshop on Selected
+ Areas in Cryptography (SAC 2000), Springer-Verlag.
+
+ [PCST1] Perrig, A., Canetti, R., Tygar, D. and D. Song, "Efficient
+ and Secure Source Authentication for Multicast", in Proc.
+ of Network and Distributed System Security Symposium NDSS
+ 2001, pp. 35-46, 2001.
+
+ [PCST2] Perrig, A., Canetti, R., Tygar, D. and D. Song, "Efficient
+ Authentication and Signing of Multicast Streams over Lossy
+ Channels", in Proc. of IEEE Security and Privacy Symposium
+ S&P2000, pp. 56-73, 2000.
+
+ [RFC1750] Eastlake, D., Crocker, S. and J. Schiller, "Randomness
+ Recommendations for Security", RFC 1750, December 1994.
+
+ [RFC2675] Borman, D., Deering, S. and R. Hinden, "IPv6 Jumbograms",
+ RFC 2675, August 1999.
+
+
+
+
+Baugher, et al. Standards Track [Page 49]
+
+RFC 3711 SRTP March 2004
+
+
+ [RFC3095] Bormann, C., Burmeister, C., Degermark, M., Fukuhsima, H.,
+ Hannu, H., Jonsson, L-E., Hakenberg, R., Koren, T., Le, K.,
+ Liu, Z., Martensson, A., Miyazaki, A., Svanbro, K., Wiebke,
+ T., Yoshimura, T. and H. Zheng, "RObust Header Compression:
+ Framework and Four Profiles: RTP, UDP, ESP, and
+ uncompressed (ROHC)", RFC 3095, July 2001.
+
+ [RFC3242] Jonsson, L-E. and G. Pelletier, "RObust Header Compression
+ (ROHC): A Link-Layer Assisted Profile for IP/UDP/RTP ", RFC
+ 3242, April 2002.
+
+ [SDMS] Andreasen, F., Baugher, M. and D. Wing, "Session
+ Description Protocol Security Descriptions for Media
+ Streams", Work in Progress.
+
+ [SWO] Svanbro, K., Wiorek, J. and B. Olin, "Voice-over-IP-over-
+ wireless", Proc. PIMRC 2000, London, Sept. 2000.
+
+ [V02] Vaudenay, S., "Security Flaws Induced by CBC Padding -
+ Application to SSL, IPsec, WTLS...", Advances in
+ Cryptology, EUROCRYPT'02, LNCS 2332, pp. 534-545.
+
+ [WC81] Wegman, M. N., and J.L. Carter, "New Hash Functions and
+ Their Use in Authentication and Set Equality", JCSS 22,
+ 265-279, 1981.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 50]
+
+RFC 3711 SRTP March 2004
+
+
+Appendix A: Pseudocode for Index Determination
+
+ The following is an example of pseudo-code for the algorithm to
+ determine the index i of an SRTP packet with sequence number SEQ. In
+ the following, signed arithmetic is assumed.
+
+ if (s_l < 32,768)
+ if (SEQ - s_l > 32,768)
+ set v to (ROC-1) mod 2^32
+ else
+ set v to ROC
+ endif
+ else
+ if (s_l - 32,768 > SEQ)
+ set v to (ROC+1) mod 2^32
+ else
+ set v to ROC
+ endif
+ endif
+ return SEQ + v*65,536
+
+Appendix B: Test Vectors
+
+ All values are in hexadecimal.
+
+B.1. AES-f8 Test Vectors
+
+ SRTP PREFIX LENGTH : 0
+
+ RTP packet header : 806e5cba50681de55c621599
+
+ RTP packet payload : 70736575646f72616e646f6d6e657373
+ 20697320746865206e65787420626573
+ 74207468696e67
+
+ ROC : d462564a
+ key : 234829008467be186c3de14aae72d62c
+ salt key : 32f2870d
+ key-mask (m) : 32f2870d555555555555555555555555
+ key XOR key-mask : 11baae0dd132eb4d3968b41ffb278379
+
+ IV : 006e5cba50681de55c621599d462564a
+ IV' : 595b699bbd3bc0df26062093c1ad8f73
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 51]
+
+RFC 3711 SRTP March 2004
+
+
+ j = 0
+ IV' xor j : 595b699bbd3bc0df26062093c1ad8f73
+ S(-1) : 00000000000000000000000000000000
+ IV' xor S(-1) xor j : 595b699bbd3bc0df26062093c1ad8f73
+ S(0) : 71ef82d70a172660240709c7fbb19d8e
+ plaintext : 70736575646f72616e646f6d6e657373
+ ciphertext : 019ce7a26e7854014a6366aa95d4eefd
+
+ j = 1
+ IV' xor j : 595b699bbd3bc0df26062093c1ad8f72
+ S(0) : 71ef82d70a172660240709c7fbb19d8e
+ IV' xor S(0) xor j : 28b4eb4cb72ce6bf020129543a1c12fc
+ S(1) : 3abd640a60919fd43bd289a09649b5fc
+ plaintext : 20697320746865206e65787420626573
+ ciphertext : 1ad4172a14f9faf455b7f1d4b62bd08f
+
+ j = 2
+ IV' xor j : 595b699bbd3bc0df26062093c1ad8f71
+ S(1) : 3abd640a60919fd43bd289a09649b5fc
+ IV' xor S(1) xor j : 63e60d91ddaa5f0b1dd4a93357e43a8d
+ S(2) : 220c7a8715266565b09ecc8a2a62b11b
+ plaintext : 74207468696e67
+ ciphertext : 562c0eef7c4802
+
+B.2. AES-CM Test Vectors
+
+ Keystream segment length: 1044512 octets (65282 AES blocks)
+ Session Key: 2B7E151628AED2A6ABF7158809CF4F3C
+ Rollover Counter: 00000000
+ Sequence Number: 0000
+ SSRC: 00000000
+ Session Salt: F0F1F2F3F4F5F6F7F8F9FAFBFCFD0000 (already shifted)
+ Offset: F0F1F2F3F4F5F6F7F8F9FAFBFCFD0000
+
+ Counter Keystream
+
+ F0F1F2F3F4F5F6F7F8F9FAFBFCFD0000 E03EAD0935C95E80E166B16DD92B4EB4
+ F0F1F2F3F4F5F6F7F8F9FAFBFCFD0001 D23513162B02D0F72A43A2FE4A5F97AB
+ F0F1F2F3F4F5F6F7F8F9FAFBFCFD0002 41E95B3BB0A2E8DD477901E4FCA894C0
+ ... ...
+ F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF EC8CDF7398607CB0F2D21675EA9EA1E4
+ F0F1F2F3F4F5F6F7F8F9FAFBFCFDFF00 362B7C3C6773516318A077D7FC5073AE
+ F0F1F2F3F4F5F6F7F8F9FAFBFCFDFF01 6A2CC3787889374FBEB4C81B17BA6C44
+
+ Nota Bene: this test case is contrived so that the latter part of the
+ keystream segment coincides with the test case in Section F.5.1 of
+ [CTR].
+
+
+
+
+Baugher, et al. Standards Track [Page 52]
+
+RFC 3711 SRTP March 2004
+
+
+B.3. Key Derivation Test Vectors
+
+ This section provides test data for the default key derivation
+ function, which uses AES-128 in Counter Mode. In the following, we
+ walk through the initial key derivation for the AES-128 Counter Mode
+ cipher, which requires a 16 octet session encryption key and a 14
+ octet session salt, and an authentication function which requires a
+ 94-octet session authentication key. These values are called the
+ cipher key, the cipher salt, and the auth key in the following.
+ Since this is the initial key derivation and the key derivation rate
+ is equal to zero, the value of (index DIV key_derivation_rate) is
+ zero (actually, a six-octet string of zeros). In the following, we
+ shorten key_derivation_rate to kdr.
+
+ The inputs to the key derivation function are the 16 octet master key
+ and the 14 octet master salt:
+
+ master key: E1F97A0D3E018BE0D64FA32C06DE4139
+ master salt: 0EC675AD498AFEEBB6960B3AABE6
+
+ We first show how the cipher key is generated. The input block for
+ AES-CM is generated by exclusive-oring the master salt with the
+ concatenation of the encryption key label 0x00 with (index DIV kdr),
+ then padding on the right with two null octets (which implements the
+ multiply-by-2^16 operation, see Section 4.3.3). The resulting value
+ is then AES-CM- encrypted using the master key to get the cipher key.
+
+ index DIV kdr: 000000000000
+ label: 00
+ master salt: 0EC675AD498AFEEBB6960B3AABE6
+ -----------------------------------------------
+ xor: 0EC675AD498AFEEBB6960B3AABE6 (x, PRF input)
+
+ x*2^16: 0EC675AD498AFEEBB6960B3AABE60000 (AES-CM input)
+
+ cipher key: C61E7A93744F39EE10734AFE3FF7A087 (AES-CM output)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 53]
+
+RFC 3711 SRTP March 2004
+
+
+ Next, we show how the cipher salt is generated. The input block for
+ AES-CM is generated by exclusive-oring the master salt with the
+ concatenation of the encryption salt label. That value is padded and
+ encrypted as above.
+
+ index DIV kdr: 000000000000
+ label: 02
+ master salt: 0EC675AD498AFEEBB6960B3AABE6
+
+ ----------------------------------------------
+ xor: 0EC675AD498AFEE9B6960B3AABE6 (x, PRF input)
+
+ x*2^16: 0EC675AD498AFEE9B6960B3AABE60000 (AES-CM input)
+
+ 30CBBC08863D8C85D49DB34A9AE17AC6 (AES-CM ouptut)
+
+ cipher salt: 30CBBC08863D8C85D49DB34A9AE1
+
+ We now show how the auth key is generated. The input block for AES-
+ CM is generated as above, but using the authentication key label.
+
+ index DIV kdr: 000000000000
+ label: 01
+ master salt: 0EC675AD498AFEEBB6960B3AABE6
+ -----------------------------------------------
+ xor: 0EC675AD498AFEEAB6960B3AABE6 (x, PRF input)
+
+ x*2^16: 0EC675AD498AFEEAB6960B3AABE60000 (AES-CM input)
+
+ Below, the auth key is shown on the left, while the corresponding AES
+ input blocks are shown on the right.
+
+ auth key AES input blocks
+ CEBE321F6FF7716B6FD4AB49AF256A15 0EC675AD498AFEEAB6960B3AABE60000
+ 6D38BAA48F0A0ACF3C34E2359E6CDBCE 0EC675AD498AFEEAB6960B3AABE60001
+ E049646C43D9327AD175578EF7227098 0EC675AD498AFEEAB6960B3AABE60002
+ 6371C10C9A369AC2F94A8C5FBCDDDC25 0EC675AD498AFEEAB6960B3AABE60003
+ 6D6E919A48B610EF17C2041E47403576 0EC675AD498AFEEAB6960B3AABE60004
+ 6B68642C59BBFC2F34DB60DBDFB2 0EC675AD498AFEEAB6960B3AABE60005
+
+
+
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 54]
+
+RFC 3711 SRTP March 2004
+
+
+Authors' Addresses
+
+ Questions and comments should be directed to the authors and
+ avt@ietf.org:
+
+ Mark Baugher
+ Cisco Systems, Inc.
+ 5510 SW Orchid Street
+ Portland, OR 97219 USA
+
+ Phone: +1 408-853-4418
+ EMail: mbaugher@cisco.com
+
+
+ Elisabetta Carrara
+ Ericsson Research
+ SE-16480 Stockholm
+ Sweden
+
+ Phone: +46 8 50877040
+ EMail: elisabetta.carrara@ericsson.com
+
+
+ David A. McGrew
+ Cisco Systems, Inc.
+ San Jose, CA 95134-1706
+ USA
+
+ Phone: +1 301-349-5815
+ EMail: mcgrew@cisco.com
+
+
+ Mats Naslund
+ Ericsson Research
+ SE-16480 Stockholm
+ Sweden
+
+ Phone: +46 8 58533739
+ EMail: mats.naslund@ericsson.com
+
+
+ Karl Norrman
+ Ericsson Research
+ SE-16480 Stockholm
+ Sweden
+
+ Phone: +46 8 4044502
+ EMail: karl.norrman@ericsson.com
+
+
+
+Baugher, et al. Standards Track [Page 55]
+
+RFC 3711 SRTP March 2004
+
+
+Full Copyright Statement
+
+ Copyright (C) The Internet Society (2004). This document is subject
+ to the rights, licenses and restrictions contained in BCP 78 and
+ except as set forth therein, the authors retain all their rights.
+
+ This document and the information contained herein are provided on an
+ "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
+ OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
+ ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
+ INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
+ INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
+ WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+Intellectual Property
+
+ The IETF takes no position regarding the validity or scope of any
+ Intellectual Property Rights or other rights that might be claimed to
+ pertain to the implementation or use of the technology described in
+ this document or the extent to which any license under such rights
+ might or might not be available; nor does it represent that it has
+ made any independent effort to identify any such rights. Information
+ on the procedures with respect to rights in RFC documents can be
+ found in BCP 78 and BCP 79.
+
+ Copies of IPR disclosures made to the IETF Secretariat and any
+ assurances of licenses to be made available, or the result of an
+ attempt made to obtain a general license or permission for the use of
+ such proprietary rights by implementers or users of this
+ specification can be obtained from the IETF on-line IPR repository at
+ http://www.ietf.org/ipr.
+
+ The IETF invites any interested party to bring to its attention any
+ copyrights, patents or patent applications, or other proprietary
+ rights that may cover technology that may be required to implement
+ this standard. Please address the information to the IETF at ietf-
+ ipr@ietf.org.
+
+Acknowledgement
+
+ Funding for the RFC Editor function is currently provided by the
+ Internet Society.
+
+
+
+
+
+
+
+
+
+Baugher, et al. Standards Track [Page 56]
+
diff --git a/jni/pjproject-android/.svn/pristine/c5/c52eb1030d140883fec01056c63639e8519649bb.svn-base b/jni/pjproject-android/.svn/pristine/c5/c52eb1030d140883fec01056c63639e8519649bb.svn-base
new file mode 100644
index 0000000..b97bdc2
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c52eb1030d140883fec01056c63639e8519649bb.svn-base
@@ -0,0 +1,12 @@
+# $Id$
+#
+from inc_cfg import *
+
+# TCP call
+test_param = TestParam(
+ "Caller requires PRACK",
+ [
+ InstanceParam("callee", "--null-audio --max-calls=1"),
+ InstanceParam("caller", "--null-audio --max-calls=1 --use-100rel")
+ ]
+ )
diff --git a/jni/pjproject-android/.svn/pristine/c5/c538b66c7110ca3a028ccfe422d0f1fa200a9935.svn-base b/jni/pjproject-android/.svn/pristine/c5/c538b66c7110ca3a028ccfe422d0f1fa200a9935.svn-base
new file mode 100644
index 0000000..3eefcb9
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c538b66c7110ca3a028ccfe422d0f1fa200a9935.svn-base
@@ -0,0 +1 @@
+1.0.0
diff --git a/jni/pjproject-android/.svn/pristine/c5/c576d862127406b98a310d13c0c2d842971ed4e4.svn-base b/jni/pjproject-android/.svn/pristine/c5/c576d862127406b98a310d13c0c2d842971ed4e4.svn-base
new file mode 100644
index 0000000..91ee183
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c576d862127406b98a310d13c0c2d842971ed4e4.svn-base
@@ -0,0 +1,121 @@
+/* $Id$ */
+/*
+ * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
+ * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+
+/* Internal */
+PJ_INLINE(void) pj_link_node(pj_list_type *prev, pj_list_type *next)
+{
+ ((pj_list*)prev)->next = next;
+ ((pj_list*)next)->prev = prev;
+}
+
+PJ_IDEF(void) pj_list_insert_after(pj_list_type *pos, pj_list_type *node)
+{
+ ((pj_list*)node)->prev = pos;
+ ((pj_list*)node)->next = ((pj_list*)pos)->next;
+ ((pj_list*) ((pj_list*)pos)->next) ->prev = node;
+ ((pj_list*)pos)->next = node;
+}
+
+
+PJ_IDEF(void) pj_list_insert_before(pj_list_type *pos, pj_list_type *node)
+{
+ pj_list_insert_after(((pj_list*)pos)->prev, node);
+}
+
+
+PJ_IDEF(void) pj_list_insert_nodes_after(pj_list_type *pos, pj_list_type *lst)
+{
+ pj_list *lst_last = (pj_list *) ((pj_list*)lst)->prev;
+ pj_list *pos_next = (pj_list *) ((pj_list*)pos)->next;
+
+ pj_link_node(pos, lst);
+ pj_link_node(lst_last, pos_next);
+}
+
+PJ_IDEF(void) pj_list_insert_nodes_before(pj_list_type *pos, pj_list_type *lst)
+{
+ pj_list_insert_nodes_after(((pj_list*)pos)->prev, lst);
+}
+
+PJ_IDEF(void) pj_list_merge_last(pj_list_type *lst1, pj_list_type *lst2)
+{
+ if (!pj_list_empty(lst2)) {
+ pj_link_node(((pj_list*)lst1)->prev, ((pj_list*)lst2)->next);
+ pj_link_node(((pj_list*)lst2)->prev, lst1);
+ pj_list_init(lst2);
+ }
+}
+
+PJ_IDEF(void) pj_list_merge_first(pj_list_type *lst1, pj_list_type *lst2)
+{
+ if (!pj_list_empty(lst2)) {
+ pj_link_node(((pj_list*)lst2)->prev, ((pj_list*)lst1)->next);
+ pj_link_node(((pj_list*)lst1), ((pj_list*)lst2)->next);
+ pj_list_init(lst2);
+ }
+}
+
+PJ_IDEF(void) pj_list_erase(pj_list_type *node)
+{
+ pj_link_node( ((pj_list*)node)->prev, ((pj_list*)node)->next);
+
+ /* It'll be safer to init the next/prev fields to itself, to
+ * prevent multiple erase() from corrupting the list. See
+ * ticket #520 for one sample bug.
+ */
+ pj_list_init(node);
+}
+
+
+PJ_IDEF(pj_list_type*) pj_list_find_node(pj_list_type *list, pj_list_type *node)
+{
+ pj_list *p = (pj_list *) ((pj_list*)list)->next;
+ while (p != list && p != node)
+ p = (pj_list *) p->next;
+
+ return p==node ? p : NULL;
+}
+
+
+PJ_IDEF(pj_list_type*) pj_list_search(pj_list_type *list, void *value,
+ int (*comp)(void *value, const pj_list_type *node))
+{
+ pj_list *p = (pj_list *) ((pj_list*)list)->next;
+ while (p != list && (*comp)(value, p) != 0)
+ p = (pj_list *) p->next;
+
+ return p==list ? NULL : p;
+}
+
+
+PJ_IDEF(pj_size_t) pj_list_size(const pj_list_type *list)
+{
+ const pj_list *node = (const pj_list*) ((const pj_list*)list)->next;
+ pj_size_t count = 0;
+
+ while (node != list) {
+ ++count;
+ node = (pj_list*)node->next;
+ }
+
+ return count;
+}
+
diff --git a/jni/pjproject-android/.svn/pristine/c5/c59453e3cd37723290cc4d8be89e19e8fa4db792.svn-base b/jni/pjproject-android/.svn/pristine/c5/c59453e3cd37723290cc4d8be89e19e8fa4db792.svn-base
new file mode 100644
index 0000000..953d115
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c59453e3cd37723290cc4d8be89e19e8fa4db792.svn-base
@@ -0,0 +1,1781 @@
+# Doxyfile 1.7.6.1
+
+# This file describes the settings to be used by the documentation system
+# doxygen (www.doxygen.org) for a project.
+#
+# All text after a hash (#) is considered a comment and will be ignored.
+# The format is:
+# TAG = value [value, ...]
+# For lists items can also be appended using:
+# TAG += value [value, ...]
+# Values that contain spaces should be placed between quotes (" ").
+
+#---------------------------------------------------------------------------
+# Project related configuration options
+#---------------------------------------------------------------------------
+
+# This tag specifies the encoding used for all characters in the config file
+# that follow. The default is UTF-8 which is also the encoding used for all
+# text before the first occurrence of this tag. Doxygen uses libiconv (or the
+# iconv built into libc) for the transcoding. See
+# http://www.gnu.org/software/libiconv for the list of possible encodings.
+
+DOXYFILE_ENCODING = UTF-8
+
+# The PROJECT_NAME tag is a single word (or sequence of words) that should
+# identify the project. Note that if you do not use Doxywizard you need
+# to put quotes around the project name if it contains spaces.
+
+PROJECT_NAME = "pjsua2"
+
+# The PROJECT_NUMBER tag can be used to enter a project or revision number.
+# This could be handy for archiving the generated documentation or
+# if some version control system is used.
+
+PROJECT_NUMBER =
+
+# Using the PROJECT_BRIEF tag one can provide an optional one line description
+# for a project that appears at the top of each page and should give viewer
+# a quick idea about the purpose of the project. Keep the description short.
+
+PROJECT_BRIEF =
+
+# With the PROJECT_LOGO tag one can specify an logo or icon that is
+# included in the documentation. The maximum height of the logo should not
+# exceed 55 pixels and the maximum width should not exceed 200 pixels.
+# Doxygen will copy the logo to the output directory.
+
+PROJECT_LOGO =
+
+# The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute)
+# base path where the generated documentation will be put.
+# If a relative path is entered, it will be relative to the location
+# where doxygen was started. If left blank the current directory will be used.
+
+OUTPUT_DIRECTORY =
+
+# If the CREATE_SUBDIRS tag is set to YES, then doxygen will create
+# 4096 sub-directories (in 2 levels) under the output directory of each output
+# format and will distribute the generated files over these directories.
+# Enabling this option can be useful when feeding doxygen a huge amount of
+# source files, where putting all generated files in the same directory would
+# otherwise cause performance problems for the file system.
+
+CREATE_SUBDIRS = NO
+
+# The OUTPUT_LANGUAGE tag is used to specify the language in which all
+# documentation generated by doxygen is written. Doxygen will use this
+# information to generate all constant output in the proper language.
+# The default language is English, other supported languages are:
+# Afrikaans, Arabic, Brazilian, Catalan, Chinese, Chinese-Traditional,
+# Croatian, Czech, Danish, Dutch, Esperanto, Farsi, Finnish, French, German,
+# Greek, Hungarian, Italian, Japanese, Japanese-en (Japanese with English
+# messages), Korean, Korean-en, Lithuanian, Norwegian, Macedonian, Persian,
+# Polish, Portuguese, Romanian, Russian, Serbian, Serbian-Cyrillic, Slovak,
+# Slovene, Spanish, Swedish, Ukrainian, and Vietnamese.
+
+OUTPUT_LANGUAGE = English
+
+# If the BRIEF_MEMBER_DESC tag is set to YES (the default) Doxygen will
+# include brief member descriptions after the members that are listed in
+# the file and class documentation (similar to JavaDoc).
+# Set to NO to disable this.
+
+BRIEF_MEMBER_DESC = YES
+
+# If the REPEAT_BRIEF tag is set to YES (the default) Doxygen will prepend
+# the brief description of a member or function before the detailed description.
+# Note: if both HIDE_UNDOC_MEMBERS and BRIEF_MEMBER_DESC are set to NO, the
+# brief descriptions will be completely suppressed.
+
+REPEAT_BRIEF = YES
+
+# This tag implements a quasi-intelligent brief description abbreviator
+# that is used to form the text in various listings. Each string
+# in this list, if found as the leading text of the brief description, will be
+# stripped from the text and the result after processing the whole list, is
+# used as the annotated text. Otherwise, the brief description is used as-is.
+# If left blank, the following values are used ("$name" is automatically
+# replaced with the name of the entity): "The $name class" "The $name widget"
+# "The $name file" "is" "provides" "specifies" "contains"
+# "represents" "a" "an" "the"
+
+ABBREVIATE_BRIEF =
+
+# If the ALWAYS_DETAILED_SEC and REPEAT_BRIEF tags are both set to YES then
+# Doxygen will generate a detailed section even if there is only a brief
+# description.
+
+ALWAYS_DETAILED_SEC = NO
+
+# If the INLINE_INHERITED_MEMB tag is set to YES, doxygen will show all
+# inherited members of a class in the documentation of that class as if those
+# members were ordinary class members. Constructors, destructors and assignment
+# operators of the base classes will not be shown.
+
+INLINE_INHERITED_MEMB = NO
+
+# If the FULL_PATH_NAMES tag is set to YES then Doxygen will prepend the full
+# path before files name in the file list and in the header files. If set
+# to NO the shortest path that makes the file name unique will be used.
+
+FULL_PATH_NAMES = YES
+
+# If the FULL_PATH_NAMES tag is set to YES then the STRIP_FROM_PATH tag
+# can be used to strip a user-defined part of the path. Stripping is
+# only done if one of the specified strings matches the left-hand part of
+# the path. The tag can be used to show relative paths in the file list.
+# If left blank the directory from which doxygen is run is used as the
+# path to strip.
+
+STRIP_FROM_PATH =
+
+# The STRIP_FROM_INC_PATH tag can be used to strip a user-defined part of
+# the path mentioned in the documentation of a class, which tells
+# the reader which header file to include in order to use a class.
+# If left blank only the name of the header file containing the class
+# definition is used. Otherwise one should specify the include paths that
+# are normally passed to the compiler using the -I flag.
+
+STRIP_FROM_INC_PATH =
+
+# If the SHORT_NAMES tag is set to YES, doxygen will generate much shorter
+# (but less readable) file names. This can be useful if your file system
+# doesn't support long names like on DOS, Mac, or CD-ROM.
+
+SHORT_NAMES = NO
+
+# If the JAVADOC_AUTOBRIEF tag is set to YES then Doxygen
+# will interpret the first line (until the first dot) of a JavaDoc-style
+# comment as the brief description. If set to NO, the JavaDoc
+# comments will behave just like regular Qt-style comments
+# (thus requiring an explicit @brief command for a brief description.)
+
+JAVADOC_AUTOBRIEF = YES
+
+# If the QT_AUTOBRIEF tag is set to YES then Doxygen will
+# interpret the first line (until the first dot) of a Qt-style
+# comment as the brief description. If set to NO, the comments
+# will behave just like regular Qt-style comments (thus requiring
+# an explicit \brief command for a brief description.)
+
+QT_AUTOBRIEF = NO
+
+# The MULTILINE_CPP_IS_BRIEF tag can be set to YES to make Doxygen
+# treat a multi-line C++ special comment block (i.e. a block of //! or ///
+# comments) as a brief description. This used to be the default behaviour.
+# The new default is to treat a multi-line C++ comment block as a detailed
+# description. Set this tag to YES if you prefer the old behaviour instead.
+
+MULTILINE_CPP_IS_BRIEF = NO
+
+# If the INHERIT_DOCS tag is set to YES (the default) then an undocumented
+# member inherits the documentation from any documented member that it
+# re-implements.
+
+INHERIT_DOCS = YES
+
+# If the SEPARATE_MEMBER_PAGES tag is set to YES, then doxygen will produce
+# a new page for each member. If set to NO, the documentation of a member will
+# be part of the file/class/namespace that contains it.
+
+SEPARATE_MEMBER_PAGES = NO
+
+# The TAB_SIZE tag can be used to set the number of spaces in a tab.
+# Doxygen uses this value to replace tabs by spaces in code fragments.
+
+TAB_SIZE = 8
+
+# This tag can be used to specify a number of aliases that acts
+# as commands in the documentation. An alias has the form "name=value".
+# For example adding "sideeffect=\par Side Effects:\n" will allow you to
+# put the command \sideeffect (or @sideeffect) in the documentation, which
+# will result in a user-defined paragraph with heading "Side Effects:".
+# You can put \n's in the value part of an alias to insert newlines.
+
+ALIASES =
+
+# This tag can be used to specify a number of word-keyword mappings (TCL only).
+# A mapping has the form "name=value". For example adding
+# "class=itcl::class" will allow you to use the command class in the
+# itcl::class meaning.
+
+TCL_SUBST =
+
+# Set the OPTIMIZE_OUTPUT_FOR_C tag to YES if your project consists of C
+# sources only. Doxygen will then generate output that is more tailored for C.
+# For instance, some of the names that are used will be different. The list
+# of all members will be omitted, etc.
+
+OPTIMIZE_OUTPUT_FOR_C = NO
+
+# Set the OPTIMIZE_OUTPUT_JAVA tag to YES if your project consists of Java
+# sources only. Doxygen will then generate output that is more tailored for
+# Java. For instance, namespaces will be presented as packages, qualified
+# scopes will look different, etc.
+
+OPTIMIZE_OUTPUT_JAVA = NO
+
+# Set the OPTIMIZE_FOR_FORTRAN tag to YES if your project consists of Fortran
+# sources only. Doxygen will then generate output that is more tailored for
+# Fortran.
+
+OPTIMIZE_FOR_FORTRAN = NO
+
+# Set the OPTIMIZE_OUTPUT_VHDL tag to YES if your project consists of VHDL
+# sources. Doxygen will then generate output that is tailored for
+# VHDL.
+
+OPTIMIZE_OUTPUT_VHDL = NO
+
+# Doxygen selects the parser to use depending on the extension of the files it
+# parses. With this tag you can assign which parser to use for a given extension.
+# Doxygen has a built-in mapping, but you can override or extend it using this
+# tag. The format is ext=language, where ext is a file extension, and language
+# is one of the parsers supported by doxygen: IDL, Java, Javascript, CSharp, C,
+# C++, D, PHP, Objective-C, Python, Fortran, VHDL, C, C++. For instance to make
+# doxygen treat .inc files as Fortran files (default is PHP), and .f files as C
+# (default is Fortran), use: inc=Fortran f=C. Note that for custom extensions
+# you also need to set FILE_PATTERNS otherwise the files are not read by doxygen.
+
+EXTENSION_MAPPING =
+
+# If you use STL classes (i.e. std::string, std::vector, etc.) but do not want
+# to include (a tag file for) the STL sources as input, then you should
+# set this tag to YES in order to let doxygen match functions declarations and
+# definitions whose arguments contain STL classes (e.g. func(std::string); v.s.
+# func(std::string) {}). This also makes the inheritance and collaboration
+# diagrams that involve STL classes more complete and accurate.
+
+BUILTIN_STL_SUPPORT = NO
+
+# If you use Microsoft's C++/CLI language, you should set this option to YES to
+# enable parsing support.
+
+CPP_CLI_SUPPORT = NO
+
+# Set the SIP_SUPPORT tag to YES if your project consists of sip sources only.
+# Doxygen will parse them like normal C++ but will assume all classes use public
+# instead of private inheritance when no explicit protection keyword is present.
+
+SIP_SUPPORT = NO
+
+# For Microsoft's IDL there are propget and propput attributes to indicate getter
+# and setter methods for a property. Setting this option to YES (the default)
+# will make doxygen replace the get and set methods by a property in the
+# documentation. This will only work if the methods are indeed getting or
+# setting a simple type. If this is not the case, or you want to show the
+# methods anyway, you should set this option to NO.
+
+IDL_PROPERTY_SUPPORT = YES
+
+# If member grouping is used in the documentation and the DISTRIBUTE_GROUP_DOC
+# tag is set to YES, then doxygen will reuse the documentation of the first
+# member in the group (if any) for the other members of the group. By default
+# all members of a group must be documented explicitly.
+
+DISTRIBUTE_GROUP_DOC = NO
+
+# Set the SUBGROUPING tag to YES (the default) to allow class member groups of
+# the same type (for instance a group of public functions) to be put as a
+# subgroup of that type (e.g. under the Public Functions section). Set it to
+# NO to prevent subgrouping. Alternatively, this can be done per class using
+# the \nosubgrouping command.
+
+SUBGROUPING = YES
+
+# When the INLINE_GROUPED_CLASSES tag is set to YES, classes, structs and
+# unions are shown inside the group in which they are included (e.g. using
+# @ingroup) instead of on a separate page (for HTML and Man pages) or
+# section (for LaTeX and RTF).
+
+INLINE_GROUPED_CLASSES = NO
+
+# When the INLINE_SIMPLE_STRUCTS tag is set to YES, structs, classes, and
+# unions with only public data fields will be shown inline in the documentation
+# of the scope in which they are defined (i.e. file, namespace, or group
+# documentation), provided this scope is documented. If set to NO (the default),
+# structs, classes, and unions are shown on a separate page (for HTML and Man
+# pages) or section (for LaTeX and RTF).
+
+INLINE_SIMPLE_STRUCTS = NO
+
+# When TYPEDEF_HIDES_STRUCT is enabled, a typedef of a struct, union, or enum
+# is documented as struct, union, or enum with the name of the typedef. So
+# typedef struct TypeS {} TypeT, will appear in the documentation as a struct
+# with name TypeT. When disabled the typedef will appear as a member of a file,
+# namespace, or class. And the struct will be named TypeS. This can typically
+# be useful for C code in case the coding convention dictates that all compound
+# types are typedef'ed and only the typedef is referenced, never the tag name.
+
+TYPEDEF_HIDES_STRUCT = NO
+
+# The SYMBOL_CACHE_SIZE determines the size of the internal cache use to
+# determine which symbols to keep in memory and which to flush to disk.
+# When the cache is full, less often used symbols will be written to disk.
+# For small to medium size projects (<1000 input files) the default value is
+# probably good enough. For larger projects a too small cache size can cause
+# doxygen to be busy swapping symbols to and from disk most of the time
+# causing a significant performance penalty.
+# If the system has enough physical memory increasing the cache will improve the
+# performance by keeping more symbols in memory. Note that the value works on
+# a logarithmic scale so increasing the size by one will roughly double the
+# memory usage. The cache size is given by this formula:
+# 2^(16+SYMBOL_CACHE_SIZE). The valid range is 0..9, the default is 0,
+# corresponding to a cache size of 2^16 = 65536 symbols.
+
+SYMBOL_CACHE_SIZE = 0
+
+# Similar to the SYMBOL_CACHE_SIZE the size of the symbol lookup cache can be
+# set using LOOKUP_CACHE_SIZE. This cache is used to resolve symbols given
+# their name and scope. Since this can be an expensive process and often the
+# same symbol appear multiple times in the code, doxygen keeps a cache of
+# pre-resolved symbols. If the cache is too small doxygen will become slower.
+# If the cache is too large, memory is wasted. The cache size is given by this
+# formula: 2^(16+LOOKUP_CACHE_SIZE). The valid range is 0..9, the default is 0,
+# corresponding to a cache size of 2^16 = 65536 symbols.
+
+LOOKUP_CACHE_SIZE = 0
+
+#---------------------------------------------------------------------------
+# Build related configuration options
+#---------------------------------------------------------------------------
+
+# If the EXTRACT_ALL tag is set to YES doxygen will assume all entities in
+# documentation are documented, even if no documentation was available.
+# Private class members and static file members will be hidden unless
+# the EXTRACT_PRIVATE and EXTRACT_STATIC tags are set to YES
+
+EXTRACT_ALL = NO
+
+# If the EXTRACT_PRIVATE tag is set to YES all private members of a class
+# will be included in the documentation.
+
+EXTRACT_PRIVATE = NO
+
+# If the EXTRACT_STATIC tag is set to YES all static members of a file
+# will be included in the documentation.
+
+EXTRACT_STATIC = NO
+
+# If the EXTRACT_LOCAL_CLASSES tag is set to YES classes (and structs)
+# defined locally in source files will be included in the documentation.
+# If set to NO only classes defined in header files are included.
+
+EXTRACT_LOCAL_CLASSES = YES
+
+# This flag is only useful for Objective-C code. When set to YES local
+# methods, which are defined in the implementation section but not in
+# the interface are included in the documentation.
+# If set to NO (the default) only methods in the interface are included.
+
+EXTRACT_LOCAL_METHODS = NO
+
+# If this flag is set to YES, the members of anonymous namespaces will be
+# extracted and appear in the documentation as a namespace called
+# 'anonymous_namespace{file}', where file will be replaced with the base
+# name of the file that contains the anonymous namespace. By default
+# anonymous namespaces are hidden.
+
+EXTRACT_ANON_NSPACES = NO
+
+# If the HIDE_UNDOC_MEMBERS tag is set to YES, Doxygen will hide all
+# undocumented members of documented classes, files or namespaces.
+# If set to NO (the default) these members will be included in the
+# various overviews, but no documentation section is generated.
+# This option has no effect if EXTRACT_ALL is enabled.
+
+HIDE_UNDOC_MEMBERS = NO
+
+# If the HIDE_UNDOC_CLASSES tag is set to YES, Doxygen will hide all
+# undocumented classes that are normally visible in the class hierarchy.
+# If set to NO (the default) these classes will be included in the various
+# overviews. This option has no effect if EXTRACT_ALL is enabled.
+
+HIDE_UNDOC_CLASSES = NO
+
+# If the HIDE_FRIEND_COMPOUNDS tag is set to YES, Doxygen will hide all
+# friend (class|struct|union) declarations.
+# If set to NO (the default) these declarations will be included in the
+# documentation.
+
+HIDE_FRIEND_COMPOUNDS = NO
+
+# If the HIDE_IN_BODY_DOCS tag is set to YES, Doxygen will hide any
+# documentation blocks found inside the body of a function.
+# If set to NO (the default) these blocks will be appended to the
+# function's detailed documentation block.
+
+HIDE_IN_BODY_DOCS = NO
+
+# The INTERNAL_DOCS tag determines if documentation
+# that is typed after a \internal command is included. If the tag is set
+# to NO (the default) then the documentation will be excluded.
+# Set it to YES to include the internal documentation.
+
+INTERNAL_DOCS = NO
+
+# If the CASE_SENSE_NAMES tag is set to NO then Doxygen will only generate
+# file names in lower-case letters. If set to YES upper-case letters are also
+# allowed. This is useful if you have classes or files whose names only differ
+# in case and if your file system supports case sensitive file names. Windows
+# and Mac users are advised to set this option to NO.
+
+CASE_SENSE_NAMES = YES
+
+# If the HIDE_SCOPE_NAMES tag is set to NO (the default) then Doxygen
+# will show members with their full class and namespace scopes in the
+# documentation. If set to YES the scope will be hidden.
+
+HIDE_SCOPE_NAMES = NO
+
+# If the SHOW_INCLUDE_FILES tag is set to YES (the default) then Doxygen
+# will put a list of the files that are included by a file in the documentation
+# of that file.
+
+SHOW_INCLUDE_FILES = YES
+
+# If the FORCE_LOCAL_INCLUDES tag is set to YES then Doxygen
+# will list include files with double quotes in the documentation
+# rather than with sharp brackets.
+
+FORCE_LOCAL_INCLUDES = NO
+
+# If the INLINE_INFO tag is set to YES (the default) then a tag [inline]
+# is inserted in the documentation for inline members.
+
+INLINE_INFO = YES
+
+# If the SORT_MEMBER_DOCS tag is set to YES (the default) then doxygen
+# will sort the (detailed) documentation of file and class members
+# alphabetically by member name. If set to NO the members will appear in
+# declaration order.
+
+SORT_MEMBER_DOCS = YES
+
+# If the SORT_BRIEF_DOCS tag is set to YES then doxygen will sort the
+# brief documentation of file, namespace and class members alphabetically
+# by member name. If set to NO (the default) the members will appear in
+# declaration order.
+
+SORT_BRIEF_DOCS = NO
+
+# If the SORT_MEMBERS_CTORS_1ST tag is set to YES then doxygen
+# will sort the (brief and detailed) documentation of class members so that
+# constructors and destructors are listed first. If set to NO (the default)
+# the constructors will appear in the respective orders defined by
+# SORT_MEMBER_DOCS and SORT_BRIEF_DOCS.
+# This tag will be ignored for brief docs if SORT_BRIEF_DOCS is set to NO
+# and ignored for detailed docs if SORT_MEMBER_DOCS is set to NO.
+
+SORT_MEMBERS_CTORS_1ST = NO
+
+# If the SORT_GROUP_NAMES tag is set to YES then doxygen will sort the
+# hierarchy of group names into alphabetical order. If set to NO (the default)
+# the group names will appear in their defined order.
+
+SORT_GROUP_NAMES = NO
+
+# If the SORT_BY_SCOPE_NAME tag is set to YES, the class list will be
+# sorted by fully-qualified names, including namespaces. If set to
+# NO (the default), the class list will be sorted only by class name,
+# not including the namespace part.
+# Note: This option is not very useful if HIDE_SCOPE_NAMES is set to YES.
+# Note: This option applies only to the class list, not to the
+# alphabetical list.
+
+SORT_BY_SCOPE_NAME = NO
+
+# If the STRICT_PROTO_MATCHING option is enabled and doxygen fails to
+# do proper type resolution of all parameters of a function it will reject a
+# match between the prototype and the implementation of a member function even
+# if there is only one candidate or it is obvious which candidate to choose
+# by doing a simple string match. By disabling STRICT_PROTO_MATCHING doxygen
+# will still accept a match between prototype and implementation in such cases.
+
+STRICT_PROTO_MATCHING = NO
+
+# The GENERATE_TODOLIST tag can be used to enable (YES) or
+# disable (NO) the todo list. This list is created by putting \todo
+# commands in the documentation.
+
+GENERATE_TODOLIST = YES
+
+# The GENERATE_TESTLIST tag can be used to enable (YES) or
+# disable (NO) the test list. This list is created by putting \test
+# commands in the documentation.
+
+GENERATE_TESTLIST = YES
+
+# The GENERATE_BUGLIST tag can be used to enable (YES) or
+# disable (NO) the bug list. This list is created by putting \bug
+# commands in the documentation.
+
+GENERATE_BUGLIST = YES
+
+# The GENERATE_DEPRECATEDLIST tag can be used to enable (YES) or
+# disable (NO) the deprecated list. This list is created by putting
+# \deprecated commands in the documentation.
+
+GENERATE_DEPRECATEDLIST= YES
+
+# The ENABLED_SECTIONS tag can be used to enable conditional
+# documentation sections, marked by \if sectionname ... \endif.
+
+ENABLED_SECTIONS =
+
+# The MAX_INITIALIZER_LINES tag determines the maximum number of lines
+# the initial value of a variable or macro consists of for it to appear in
+# the documentation. If the initializer consists of more lines than specified
+# here it will be hidden. Use a value of 0 to hide initializers completely.
+# The appearance of the initializer of individual variables and macros in the
+# documentation can be controlled using \showinitializer or \hideinitializer
+# command in the documentation regardless of this setting.
+
+MAX_INITIALIZER_LINES = 30
+
+# Set the SHOW_USED_FILES tag to NO to disable the list of files generated
+# at the bottom of the documentation of classes and structs. If set to YES the
+# list will mention the files that were used to generate the documentation.
+
+SHOW_USED_FILES = YES
+
+# If the sources in your project are distributed over multiple directories
+# then setting the SHOW_DIRECTORIES tag to YES will show the directory hierarchy
+# in the documentation. The default is NO.
+
+SHOW_DIRECTORIES = NO
+
+# Set the SHOW_FILES tag to NO to disable the generation of the Files page.
+# This will remove the Files entry from the Quick Index and from the
+# Folder Tree View (if specified). The default is YES.
+
+SHOW_FILES = YES
+
+# Set the SHOW_NAMESPACES tag to NO to disable the generation of the
+# Namespaces page.
+# This will remove the Namespaces entry from the Quick Index
+# and from the Folder Tree View (if specified). The default is YES.
+
+SHOW_NAMESPACES = YES
+
+# The FILE_VERSION_FILTER tag can be used to specify a program or script that
+# doxygen should invoke to get the current version for each file (typically from
+# the version control system). Doxygen will invoke the program by executing (via
+# popen()) the command <command> <input-file>, where <command> is the value of
+# the FILE_VERSION_FILTER tag, and <input-file> is the name of an input file
+# provided by doxygen. Whatever the program writes to standard output
+# is used as the file version. See the manual for examples.
+
+FILE_VERSION_FILTER =
+
+# The LAYOUT_FILE tag can be used to specify a layout file which will be parsed
+# by doxygen. The layout file controls the global structure of the generated
+# output files in an output format independent way. The create the layout file
+# that represents doxygen's defaults, run doxygen with the -l option.
+# You can optionally specify a file name after the option, if omitted
+# DoxygenLayout.xml will be used as the name of the layout file.
+
+LAYOUT_FILE =
+
+# The CITE_BIB_FILES tag can be used to specify one or more bib files
+# containing the references data. This must be a list of .bib files. The
+# .bib extension is automatically appended if omitted. Using this command
+# requires the bibtex tool to be installed. See also
+# http://en.wikipedia.org/wiki/BibTeX for more info. For LaTeX the style
+# of the bibliography can be controlled using LATEX_BIB_STYLE. To use this
+# feature you need bibtex and perl available in the search path.
+
+CITE_BIB_FILES =
+
+#---------------------------------------------------------------------------
+# configuration options related to warning and progress messages
+#---------------------------------------------------------------------------
+
+# The QUIET tag can be used to turn on/off the messages that are generated
+# by doxygen. Possible values are YES and NO. If left blank NO is used.
+
+QUIET = YES
+
+# The WARNINGS tag can be used to turn on/off the warning messages that are
+# generated by doxygen. Possible values are YES and NO. If left blank
+# NO is used.
+
+WARNINGS = YES
+
+# If WARN_IF_UNDOCUMENTED is set to YES, then doxygen will generate warnings
+# for undocumented members. If EXTRACT_ALL is set to YES then this flag will
+# automatically be disabled.
+
+WARN_IF_UNDOCUMENTED = YES
+
+# If WARN_IF_DOC_ERROR is set to YES, doxygen will generate warnings for
+# potential errors in the documentation, such as not documenting some
+# parameters in a documented function, or documenting parameters that
+# don't exist or using markup commands wrongly.
+
+WARN_IF_DOC_ERROR = YES
+
+# The WARN_NO_PARAMDOC option can be enabled to get warnings for
+# functions that are documented, but have no documentation for their parameters
+# or return value. If set to NO (the default) doxygen will only warn about
+# wrong or incomplete parameter documentation, but not about the absence of
+# documentation.
+
+WARN_NO_PARAMDOC = NO
+
+# The WARN_FORMAT tag determines the format of the warning messages that
+# doxygen can produce. The string should contain the $file, $line, and $text
+# tags, which will be replaced by the file and line number from which the
+# warning originated and the warning text. Optionally the format may contain
+# $version, which will be replaced by the version of the file (if it could
+# be obtained via FILE_VERSION_FILTER)
+
+WARN_FORMAT = "$file:$line: $text"
+
+# The WARN_LOGFILE tag can be used to specify a file to which warning
+# and error messages should be written. If left blank the output is written
+# to stderr.
+
+WARN_LOGFILE =
+
+#---------------------------------------------------------------------------
+# configuration options related to the input files
+#---------------------------------------------------------------------------
+
+# The INPUT tag can be used to specify the files and/or directories that contain
+# documented source files. You may enter file names like "myfile.cpp" or
+# directories like "/usr/src/myproject". Separate the files or directories
+# with spaces.
+
+INPUT = ../../pjsip/include/pjsua2/media.hpp
+
+# This tag can be used to specify the character encoding of the source files
+# that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is
+# also the default input encoding. Doxygen uses libiconv (or the iconv built
+# into libc) for the transcoding. See http://www.gnu.org/software/libiconv for
+# the list of possible encodings.
+
+INPUT_ENCODING = UTF-8
+
+# If the value of the INPUT tag contains directories, you can use the
+# FILE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp
+# and *.h) to filter out the source-files in the directories. If left
+# blank the following patterns are tested:
+# *.c *.cc *.cxx *.cpp *.c++ *.d *.java *.ii *.ixx *.ipp *.i++ *.inl *.h *.hh
+# *.hxx *.hpp *.h++ *.idl *.odl *.cs *.php *.php3 *.inc *.m *.mm *.dox *.py
+# *.f90 *.f *.for *.vhd *.vhdl
+
+FILE_PATTERNS = *.hpp
+
+# The RECURSIVE tag can be used to turn specify whether or not subdirectories
+# should be searched for input files as well. Possible values are YES and NO.
+# If left blank NO is used.
+
+RECURSIVE = NO
+
+# The EXCLUDE tag can be used to specify files and/or directories that should be
+# excluded from the INPUT source files. This way you can easily exclude a
+# subdirectory from a directory tree whose root is specified with the INPUT tag.
+# Note that relative paths are relative to the directory from which doxygen is
+# run.
+
+EXCLUDE =
+
+# The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
+# directories that are symbolic links (a Unix file system feature) are excluded
+# from the input.
+
+EXCLUDE_SYMLINKS = NO
+
+# If the value of the INPUT tag contains directories, you can use the
+# EXCLUDE_PATTERNS tag to specify one or more wildcard patterns to exclude
+# certain files from those directories. Note that the wildcards are matched
+# against the file with absolute path, so to exclude all test directories
+# for example use the pattern */test/*
+
+EXCLUDE_PATTERNS =
+
+# The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names
+# (namespaces, classes, functions, etc.) that should be excluded from the
+# output. The symbol name can be a fully qualified name, a word, or if the
+# wildcard * is used, a substring. Examples: ANamespace, AClass,
+# AClass::ANamespace, ANamespace::*Test
+
+EXCLUDE_SYMBOLS =
+
+# The EXAMPLE_PATH tag can be used to specify one or more files or
+# directories that contain example code fragments that are included (see
+# the \include command).
+
+EXAMPLE_PATH =
+
+# If the value of the EXAMPLE_PATH tag contains directories, you can use the
+# EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp
+# and *.h) to filter out the source-files in the directories. If left
+# blank all files are included.
+
+EXAMPLE_PATTERNS =
+
+# If the EXAMPLE_RECURSIVE tag is set to YES then subdirectories will be
+# searched for input files to be used with the \include or \dontinclude
+# commands irrespective of the value of the RECURSIVE tag.
+# Possible values are YES and NO. If left blank NO is used.
+
+EXAMPLE_RECURSIVE = NO
+
+# The IMAGE_PATH tag can be used to specify one or more files or
+# directories that contain image that are included in the documentation (see
+# the \image command).
+
+IMAGE_PATH =
+
+# The INPUT_FILTER tag can be used to specify a program that doxygen should
+# invoke to filter for each input file. Doxygen will invoke the filter program
+# by executing (via popen()) the command <filter> <input-file>, where <filter>
+# is the value of the INPUT_FILTER tag, and <input-file> is the name of an
+# input file. Doxygen will then use the output that the filter program writes
+# to standard output.
+# If FILTER_PATTERNS is specified, this tag will be
+# ignored.
+
+INPUT_FILTER =
+
+# The FILTER_PATTERNS tag can be used to specify filters on a per file pattern
+# basis.
+# Doxygen will compare the file name with each pattern and apply the
+# filter if there is a match.
+# The filters are a list of the form:
+# pattern=filter (like *.cpp=my_cpp_filter). See INPUT_FILTER for further
+# info on how filters are used. If FILTER_PATTERNS is empty or if
+# non of the patterns match the file name, INPUT_FILTER is applied.
+
+FILTER_PATTERNS =
+
+# If the FILTER_SOURCE_FILES tag is set to YES, the input filter (if set using
+# INPUT_FILTER) will be used to filter the input files when producing source
+# files to browse (i.e. when SOURCE_BROWSER is set to YES).
+
+FILTER_SOURCE_FILES = NO
+
+# The FILTER_SOURCE_PATTERNS tag can be used to specify source filters per file
+# pattern. A pattern will override the setting for FILTER_PATTERN (if any)
+# and it is also possible to disable source filtering for a specific pattern
+# using *.ext= (so without naming a filter). This option only has effect when
+# FILTER_SOURCE_FILES is enabled.
+
+FILTER_SOURCE_PATTERNS =
+
+#---------------------------------------------------------------------------
+# configuration options related to source browsing
+#---------------------------------------------------------------------------
+
+# If the SOURCE_BROWSER tag is set to YES then a list of source files will
+# be generated. Documented entities will be cross-referenced with these sources.
+# Note: To get rid of all source code in the generated output, make sure also
+# VERBATIM_HEADERS is set to NO.
+
+SOURCE_BROWSER = NO
+
+# Setting the INLINE_SOURCES tag to YES will include the body
+# of functions and classes directly in the documentation.
+
+INLINE_SOURCES = NO
+
+# Setting the STRIP_CODE_COMMENTS tag to YES (the default) will instruct
+# doxygen to hide any special comment blocks from generated source code
+# fragments. Normal C and C++ comments will always remain visible.
+
+STRIP_CODE_COMMENTS = YES
+
+# If the REFERENCED_BY_RELATION tag is set to YES
+# then for each documented function all documented
+# functions referencing it will be listed.
+
+REFERENCED_BY_RELATION = NO
+
+# If the REFERENCES_RELATION tag is set to YES
+# then for each documented function all documented entities
+# called/used by that function will be listed.
+
+REFERENCES_RELATION = NO
+
+# If the REFERENCES_LINK_SOURCE tag is set to YES (the default)
+# and SOURCE_BROWSER tag is set to YES, then the hyperlinks from
+# functions in REFERENCES_RELATION and REFERENCED_BY_RELATION lists will
+# link to the source code.
+# Otherwise they will link to the documentation.
+
+REFERENCES_LINK_SOURCE = YES
+
+# If the USE_HTAGS tag is set to YES then the references to source code
+# will point to the HTML generated by the htags(1) tool instead of doxygen
+# built-in source browser. The htags tool is part of GNU's global source
+# tagging system (see http://www.gnu.org/software/global/global.html). You
+# will need version 4.8.6 or higher.
+
+USE_HTAGS = NO
+
+# If the VERBATIM_HEADERS tag is set to YES (the default) then Doxygen
+# will generate a verbatim copy of the header file for each class for
+# which an include is specified. Set to NO to disable this.
+
+VERBATIM_HEADERS = YES
+
+#---------------------------------------------------------------------------
+# configuration options related to the alphabetical class index
+#---------------------------------------------------------------------------
+
+# If the ALPHABETICAL_INDEX tag is set to YES, an alphabetical index
+# of all compounds will be generated. Enable this if the project
+# contains a lot of classes, structs, unions or interfaces.
+
+ALPHABETICAL_INDEX = YES
+
+# If the alphabetical index is enabled (see ALPHABETICAL_INDEX) then
+# the COLS_IN_ALPHA_INDEX tag can be used to specify the number of columns
+# in which this list will be split (can be a number in the range [1..20])
+
+COLS_IN_ALPHA_INDEX = 5
+
+# In case all classes in a project start with a common prefix, all
+# classes will be put under the same header in the alphabetical index.
+# The IGNORE_PREFIX tag can be used to specify one or more prefixes that
+# should be ignored while generating the index headers.
+
+IGNORE_PREFIX =
+
+#---------------------------------------------------------------------------
+# configuration options related to the HTML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_HTML tag is set to YES (the default) Doxygen will
+# generate HTML output.
+
+GENERATE_HTML = NO
+
+# The HTML_OUTPUT tag is used to specify where the HTML docs will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `html' will be used as the default path.
+
+HTML_OUTPUT = html
+
+# The HTML_FILE_EXTENSION tag can be used to specify the file extension for
+# each generated HTML page (for example: .htm,.php,.asp). If it is left blank
+# doxygen will generate files with .html extension.
+
+HTML_FILE_EXTENSION = .html
+
+# The HTML_HEADER tag can be used to specify a personal HTML header for
+# each generated HTML page. If it is left blank doxygen will generate a
+# standard header. Note that when using a custom header you are responsible
+# for the proper inclusion of any scripts and style sheets that doxygen
+# needs, which is dependent on the configuration options used.
+# It is advised to generate a default header using "doxygen -w html
+# header.html footer.html stylesheet.css YourConfigFile" and then modify
+# that header. Note that the header is subject to change so you typically
+# have to redo this when upgrading to a newer version of doxygen or when
+# changing the value of configuration settings such as GENERATE_TREEVIEW!
+
+HTML_HEADER =
+
+# The HTML_FOOTER tag can be used to specify a personal HTML footer for
+# each generated HTML page. If it is left blank doxygen will generate a
+# standard footer.
+
+HTML_FOOTER =
+
+# The HTML_STYLESHEET tag can be used to specify a user-defined cascading
+# style sheet that is used by each HTML page. It can be used to
+# fine-tune the look of the HTML output. If the tag is left blank doxygen
+# will generate a default style sheet. Note that doxygen will try to copy
+# the style sheet file to the HTML output directory, so don't put your own
+# style sheet in the HTML output directory as well, or it will be erased!
+
+HTML_STYLESHEET =
+
+# The HTML_EXTRA_FILES tag can be used to specify one or more extra images or
+# other source files which should be copied to the HTML output directory. Note
+# that these files will be copied to the base HTML output directory. Use the
+# $relpath$ marker in the HTML_HEADER and/or HTML_FOOTER files to load these
+# files. In the HTML_STYLESHEET file, use the file name only. Also note that
+# the files will be copied as-is; there are no commands or markers available.
+
+HTML_EXTRA_FILES =
+
+# The HTML_COLORSTYLE_HUE tag controls the color of the HTML output.
+# Doxygen will adjust the colors in the style sheet and background images
+# according to this color. Hue is specified as an angle on a colorwheel,
+# see http://en.wikipedia.org/wiki/Hue for more information.
+# For instance the value 0 represents red, 60 is yellow, 120 is green,
+# 180 is cyan, 240 is blue, 300 purple, and 360 is red again.
+# The allowed range is 0 to 359.
+
+HTML_COLORSTYLE_HUE = 220
+
+# The HTML_COLORSTYLE_SAT tag controls the purity (or saturation) of
+# the colors in the HTML output. For a value of 0 the output will use
+# grayscales only. A value of 255 will produce the most vivid colors.
+
+HTML_COLORSTYLE_SAT = 100
+
+# The HTML_COLORSTYLE_GAMMA tag controls the gamma correction applied to
+# the luminance component of the colors in the HTML output. Values below
+# 100 gradually make the output lighter, whereas values above 100 make
+# the output darker. The value divided by 100 is the actual gamma applied,
+# so 80 represents a gamma of 0.8, The value 220 represents a gamma of 2.2,
+# and 100 does not change the gamma.
+
+HTML_COLORSTYLE_GAMMA = 80
+
+# If the HTML_TIMESTAMP tag is set to YES then the footer of each generated HTML
+# page will contain the date and time when the page was generated. Setting
+# this to NO can help when comparing the output of multiple runs.
+
+HTML_TIMESTAMP = YES
+
+# If the HTML_ALIGN_MEMBERS tag is set to YES, the members of classes,
+# files or namespaces will be aligned in HTML using tables. If set to
+# NO a bullet list will be used.
+
+HTML_ALIGN_MEMBERS = YES
+
+# If the HTML_DYNAMIC_SECTIONS tag is set to YES then the generated HTML
+# documentation will contain sections that can be hidden and shown after the
+# page has loaded. For this to work a browser that supports
+# JavaScript and DHTML is required (for instance Mozilla 1.0+, Firefox
+# Netscape 6.0+, Internet explorer 5.0+, Konqueror, or Safari).
+
+HTML_DYNAMIC_SECTIONS = NO
+
+# If the GENERATE_DOCSET tag is set to YES, additional index files
+# will be generated that can be used as input for Apple's Xcode 3
+# integrated development environment, introduced with OSX 10.5 (Leopard).
+# To create a documentation set, doxygen will generate a Makefile in the
+# HTML output directory. Running make will produce the docset in that
+# directory and running "make install" will install the docset in
+# ~/Library/Developer/Shared/Documentation/DocSets so that Xcode will find
+# it at startup.
+# See http://developer.apple.com/tools/creatingdocsetswithdoxygen.html
+# for more information.
+
+GENERATE_DOCSET = NO
+
+# When GENERATE_DOCSET tag is set to YES, this tag determines the name of the
+# feed. A documentation feed provides an umbrella under which multiple
+# documentation sets from a single provider (such as a company or product suite)
+# can be grouped.
+
+DOCSET_FEEDNAME = "Doxygen generated docs"
+
+# When GENERATE_DOCSET tag is set to YES, this tag specifies a string that
+# should uniquely identify the documentation set bundle. This should be a
+# reverse domain-name style string, e.g. com.mycompany.MyDocSet. Doxygen
+# will append .docset to the name.
+
+DOCSET_BUNDLE_ID = org.doxygen.Project
+
+# When GENERATE_PUBLISHER_ID tag specifies a string that should uniquely identify
+# the documentation publisher. This should be a reverse domain-name style
+# string, e.g. com.mycompany.MyDocSet.documentation.
+
+DOCSET_PUBLISHER_ID = org.doxygen.Publisher
+
+# The GENERATE_PUBLISHER_NAME tag identifies the documentation publisher.
+
+DOCSET_PUBLISHER_NAME = Publisher
+
+# If the GENERATE_HTMLHELP tag is set to YES, additional index files
+# will be generated that can be used as input for tools like the
+# Microsoft HTML help workshop to generate a compiled HTML help file (.chm)
+# of the generated HTML documentation.
+
+GENERATE_HTMLHELP = NO
+
+# If the GENERATE_HTMLHELP tag is set to YES, the CHM_FILE tag can
+# be used to specify the file name of the resulting .chm file. You
+# can add a path in front of the file if the result should not be
+# written to the html output directory.
+
+CHM_FILE =
+
+# If the GENERATE_HTMLHELP tag is set to YES, the HHC_LOCATION tag can
+# be used to specify the location (absolute path including file name) of
+# the HTML help compiler (hhc.exe). If non-empty doxygen will try to run
+# the HTML help compiler on the generated index.hhp.
+
+HHC_LOCATION =
+
+# If the GENERATE_HTMLHELP tag is set to YES, the GENERATE_CHI flag
+# controls if a separate .chi index file is generated (YES) or that
+# it should be included in the master .chm file (NO).
+
+GENERATE_CHI = NO
+
+# If the GENERATE_HTMLHELP tag is set to YES, the CHM_INDEX_ENCODING
+# is used to encode HtmlHelp index (hhk), content (hhc) and project file
+# content.
+
+CHM_INDEX_ENCODING =
+
+# If the GENERATE_HTMLHELP tag is set to YES, the BINARY_TOC flag
+# controls whether a binary table of contents is generated (YES) or a
+# normal table of contents (NO) in the .chm file.
+
+BINARY_TOC = NO
+
+# The TOC_EXPAND flag can be set to YES to add extra items for group members
+# to the contents of the HTML help documentation and to the tree view.
+
+TOC_EXPAND = NO
+
+# If the GENERATE_QHP tag is set to YES and both QHP_NAMESPACE and
+# QHP_VIRTUAL_FOLDER are set, an additional index file will be generated
+# that can be used as input for Qt's qhelpgenerator to generate a
+# Qt Compressed Help (.qch) of the generated HTML documentation.
+
+GENERATE_QHP = NO
+
+# If the QHG_LOCATION tag is specified, the QCH_FILE tag can
+# be used to specify the file name of the resulting .qch file.
+# The path specified is relative to the HTML output folder.
+
+QCH_FILE =
+
+# The QHP_NAMESPACE tag specifies the namespace to use when generating
+# Qt Help Project output. For more information please see
+# http://doc.trolltech.com/qthelpproject.html#namespace
+
+QHP_NAMESPACE = org.doxygen.Project
+
+# The QHP_VIRTUAL_FOLDER tag specifies the namespace to use when generating
+# Qt Help Project output. For more information please see
+# http://doc.trolltech.com/qthelpproject.html#virtual-folders
+
+QHP_VIRTUAL_FOLDER = doc
+
+# If QHP_CUST_FILTER_NAME is set, it specifies the name of a custom filter to
+# add. For more information please see
+# http://doc.trolltech.com/qthelpproject.html#custom-filters
+
+QHP_CUST_FILTER_NAME =
+
+# The QHP_CUST_FILT_ATTRS tag specifies the list of the attributes of the
+# custom filter to add. For more information please see
+# <a href="http://doc.trolltech.com/qthelpproject.html#custom-filters">
+# Qt Help Project / Custom Filters</a>.
+
+QHP_CUST_FILTER_ATTRS =
+
+# The QHP_SECT_FILTER_ATTRS tag specifies the list of the attributes this
+# project's
+# filter section matches.
+# <a href="http://doc.trolltech.com/qthelpproject.html#filter-attributes">
+# Qt Help Project / Filter Attributes</a>.
+
+QHP_SECT_FILTER_ATTRS =
+
+# If the GENERATE_QHP tag is set to YES, the QHG_LOCATION tag can
+# be used to specify the location of Qt's qhelpgenerator.
+# If non-empty doxygen will try to run qhelpgenerator on the generated
+# .qhp file.
+
+QHG_LOCATION =
+
+# If the GENERATE_ECLIPSEHELP tag is set to YES, additional index files
+# will be generated, which together with the HTML files, form an Eclipse help
+# plugin. To install this plugin and make it available under the help contents
+# menu in Eclipse, the contents of the directory containing the HTML and XML
+# files needs to be copied into the plugins directory of eclipse. The name of
+# the directory within the plugins directory should be the same as
+# the ECLIPSE_DOC_ID value. After copying Eclipse needs to be restarted before
+# the help appears.
+
+GENERATE_ECLIPSEHELP = NO
+
+# A unique identifier for the eclipse help plugin. When installing the plugin
+# the directory name containing the HTML and XML files should also have
+# this name.
+
+ECLIPSE_DOC_ID = org.doxygen.Project
+
+# The DISABLE_INDEX tag can be used to turn on/off the condensed index (tabs)
+# at top of each HTML page. The value NO (the default) enables the index and
+# the value YES disables it. Since the tabs have the same information as the
+# navigation tree you can set this option to NO if you already set
+# GENERATE_TREEVIEW to YES.
+
+DISABLE_INDEX = NO
+
+# The GENERATE_TREEVIEW tag is used to specify whether a tree-like index
+# structure should be generated to display hierarchical information.
+# If the tag value is set to YES, a side panel will be generated
+# containing a tree-like index structure (just like the one that
+# is generated for HTML Help). For this to work a browser that supports
+# JavaScript, DHTML, CSS and frames is required (i.e. any modern browser).
+# Windows users are probably better off using the HTML help feature.
+# Since the tree basically has the same information as the tab index you
+# could consider to set DISABLE_INDEX to NO when enabling this option.
+
+GENERATE_TREEVIEW = NO
+
+# The ENUM_VALUES_PER_LINE tag can be used to set the number of enum values
+# (range [0,1..20]) that doxygen will group on one line in the generated HTML
+# documentation. Note that a value of 0 will completely suppress the enum
+# values from appearing in the overview section.
+
+ENUM_VALUES_PER_LINE = 4
+
+# By enabling USE_INLINE_TREES, doxygen will generate the Groups, Directories,
+# and Class Hierarchy pages using a tree view instead of an ordered list.
+
+USE_INLINE_TREES = NO
+
+# If the treeview is enabled (see GENERATE_TREEVIEW) then this tag can be
+# used to set the initial width (in pixels) of the frame in which the tree
+# is shown.
+
+TREEVIEW_WIDTH = 250
+
+# When the EXT_LINKS_IN_WINDOW option is set to YES doxygen will open
+# links to external symbols imported via tag files in a separate window.
+
+EXT_LINKS_IN_WINDOW = NO
+
+# Use this tag to change the font size of Latex formulas included
+# as images in the HTML documentation. The default is 10. Note that
+# when you change the font size after a successful doxygen run you need
+# to manually remove any form_*.png images from the HTML output directory
+# to force them to be regenerated.
+
+FORMULA_FONTSIZE = 10
+
+# Use the FORMULA_TRANPARENT tag to determine whether or not the images
+# generated for formulas are transparent PNGs. Transparent PNGs are
+# not supported properly for IE 6.0, but are supported on all modern browsers.
+# Note that when changing this option you need to delete any form_*.png files
+# in the HTML output before the changes have effect.
+
+FORMULA_TRANSPARENT = YES
+
+# Enable the USE_MATHJAX option to render LaTeX formulas using MathJax
+# (see http://www.mathjax.org) which uses client side Javascript for the
+# rendering instead of using prerendered bitmaps. Use this if you do not
+# have LaTeX installed or if you want to formulas look prettier in the HTML
+# output. When enabled you also need to install MathJax separately and
+# configure the path to it using the MATHJAX_RELPATH option.
+
+USE_MATHJAX = NO
+
+# When MathJax is enabled you need to specify the location relative to the
+# HTML output directory using the MATHJAX_RELPATH option. The destination
+# directory should contain the MathJax.js script. For instance, if the mathjax
+# directory is located at the same level as the HTML output directory, then
+# MATHJAX_RELPATH should be ../mathjax. The default value points to the
+# mathjax.org site, so you can quickly see the result without installing
+# MathJax, but it is strongly recommended to install a local copy of MathJax
+# before deployment.
+
+MATHJAX_RELPATH = http://www.mathjax.org/mathjax
+
+# The MATHJAX_EXTENSIONS tag can be used to specify one or MathJax extension
+# names that should be enabled during MathJax rendering.
+
+MATHJAX_EXTENSIONS =
+
+# When the SEARCHENGINE tag is enabled doxygen will generate a search box
+# for the HTML output. The underlying search engine uses javascript
+# and DHTML and should work on any modern browser. Note that when using
+# HTML help (GENERATE_HTMLHELP), Qt help (GENERATE_QHP), or docsets
+# (GENERATE_DOCSET) there is already a search function so this one should
+# typically be disabled. For large projects the javascript based search engine
+# can be slow, then enabling SERVER_BASED_SEARCH may provide a better solution.
+
+SEARCHENGINE = YES
+
+# When the SERVER_BASED_SEARCH tag is enabled the search engine will be
+# implemented using a PHP enabled web server instead of at the web client
+# using Javascript. Doxygen will generate the search PHP script and index
+# file to put on the web server. The advantage of the server
+# based approach is that it scales better to large projects and allows
+# full text search. The disadvantages are that it is more difficult to setup
+# and does not have live searching capabilities.
+
+SERVER_BASED_SEARCH = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to the LaTeX output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_LATEX tag is set to YES (the default) Doxygen will
+# generate Latex output.
+
+GENERATE_LATEX = NO
+
+# The LATEX_OUTPUT tag is used to specify where the LaTeX docs will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `latex' will be used as the default path.
+
+LATEX_OUTPUT = latex
+
+# The LATEX_CMD_NAME tag can be used to specify the LaTeX command name to be
+# invoked. If left blank `latex' will be used as the default command name.
+# Note that when enabling USE_PDFLATEX this option is only used for
+# generating bitmaps for formulas in the HTML output, but not in the
+# Makefile that is written to the output directory.
+
+LATEX_CMD_NAME = latex
+
+# The MAKEINDEX_CMD_NAME tag can be used to specify the command name to
+# generate index for LaTeX. If left blank `makeindex' will be used as the
+# default command name.
+
+MAKEINDEX_CMD_NAME = makeindex
+
+# If the COMPACT_LATEX tag is set to YES Doxygen generates more compact
+# LaTeX documents. This may be useful for small projects and may help to
+# save some trees in general.
+
+COMPACT_LATEX = NO
+
+# The PAPER_TYPE tag can be used to set the paper type that is used
+# by the printer. Possible values are: a4, letter, legal and
+# executive. If left blank a4wide will be used.
+
+PAPER_TYPE = a4
+
+# The EXTRA_PACKAGES tag can be to specify one or more names of LaTeX
+# packages that should be included in the LaTeX output.
+
+EXTRA_PACKAGES =
+
+# The LATEX_HEADER tag can be used to specify a personal LaTeX header for
+# the generated latex document. The header should contain everything until
+# the first chapter. If it is left blank doxygen will generate a
+# standard header. Notice: only use this tag if you know what you are doing!
+
+LATEX_HEADER =
+
+# The LATEX_FOOTER tag can be used to specify a personal LaTeX footer for
+# the generated latex document. The footer should contain everything after
+# the last chapter. If it is left blank doxygen will generate a
+# standard footer. Notice: only use this tag if you know what you are doing!
+
+LATEX_FOOTER =
+
+# If the PDF_HYPERLINKS tag is set to YES, the LaTeX that is generated
+# is prepared for conversion to pdf (using ps2pdf). The pdf file will
+# contain links (just like the HTML output) instead of page references
+# This makes the output suitable for online browsing using a pdf viewer.
+
+PDF_HYPERLINKS = YES
+
+# If the USE_PDFLATEX tag is set to YES, pdflatex will be used instead of
+# plain latex in the generated Makefile. Set this option to YES to get a
+# higher quality PDF documentation.
+
+USE_PDFLATEX = YES
+
+# If the LATEX_BATCHMODE tag is set to YES, doxygen will add the \\batchmode.
+# command to the generated LaTeX files. This will instruct LaTeX to keep
+# running if errors occur, instead of asking the user for help.
+# This option is also used when generating formulas in HTML.
+
+LATEX_BATCHMODE = NO
+
+# If LATEX_HIDE_INDICES is set to YES then doxygen will not
+# include the index chapters (such as File Index, Compound Index, etc.)
+# in the output.
+
+LATEX_HIDE_INDICES = NO
+
+# If LATEX_SOURCE_CODE is set to YES then doxygen will include
+# source code with syntax highlighting in the LaTeX output.
+# Note that which sources are shown also depends on other settings
+# such as SOURCE_BROWSER.
+
+LATEX_SOURCE_CODE = NO
+
+# The LATEX_BIB_STYLE tag can be used to specify the style to use for the
+# bibliography, e.g. plainnat, or ieeetr. The default style is "plain". See
+# http://en.wikipedia.org/wiki/BibTeX for more info.
+
+LATEX_BIB_STYLE = plain
+
+#---------------------------------------------------------------------------
+# configuration options related to the RTF output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_RTF tag is set to YES Doxygen will generate RTF output
+# The RTF output is optimized for Word 97 and may not look very pretty with
+# other RTF readers or editors.
+
+GENERATE_RTF = NO
+
+# The RTF_OUTPUT tag is used to specify where the RTF docs will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `rtf' will be used as the default path.
+
+RTF_OUTPUT = rtf
+
+# If the COMPACT_RTF tag is set to YES Doxygen generates more compact
+# RTF documents. This may be useful for small projects and may help to
+# save some trees in general.
+
+COMPACT_RTF = NO
+
+# If the RTF_HYPERLINKS tag is set to YES, the RTF that is generated
+# will contain hyperlink fields. The RTF file will
+# contain links (just like the HTML output) instead of page references.
+# This makes the output suitable for online browsing using WORD or other
+# programs which support those fields.
+# Note: wordpad (write) and others do not support links.
+
+RTF_HYPERLINKS = NO
+
+# Load style sheet definitions from file. Syntax is similar to doxygen's
+# config file, i.e. a series of assignments. You only have to provide
+# replacements, missing definitions are set to their default value.
+
+RTF_STYLESHEET_FILE =
+
+# Set optional variables used in the generation of an rtf document.
+# Syntax is similar to doxygen's config file.
+
+RTF_EXTENSIONS_FILE =
+
+#---------------------------------------------------------------------------
+# configuration options related to the man page output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_MAN tag is set to YES (the default) Doxygen will
+# generate man pages
+
+GENERATE_MAN = NO
+
+# The MAN_OUTPUT tag is used to specify where the man pages will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `man' will be used as the default path.
+
+MAN_OUTPUT = man
+
+# The MAN_EXTENSION tag determines the extension that is added to
+# the generated man pages (default is the subroutine's section .3)
+
+MAN_EXTENSION = .3
+
+# If the MAN_LINKS tag is set to YES and Doxygen generates man output,
+# then it will generate one additional man file for each entity
+# documented in the real man page(s). These additional files
+# only source the real man page, but without them the man command
+# would be unable to find the correct page. The default is NO.
+
+MAN_LINKS = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to the XML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_XML tag is set to YES Doxygen will
+# generate an XML file that captures the structure of
+# the code including all documentation.
+
+GENERATE_XML = YES
+
+# The XML_OUTPUT tag is used to specify where the XML pages will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `xml' will be used as the default path.
+
+XML_OUTPUT = xml
+
+# The XML_SCHEMA tag can be used to specify an XML schema,
+# which can be used by a validating XML parser to check the
+# syntax of the XML files.
+
+XML_SCHEMA =
+
+# The XML_DTD tag can be used to specify an XML DTD,
+# which can be used by a validating XML parser to check the
+# syntax of the XML files.
+
+XML_DTD =
+
+# If the XML_PROGRAMLISTING tag is set to YES Doxygen will
+# dump the program listings (including syntax highlighting
+# and cross-referencing information) to the XML output. Note that
+# enabling this will significantly increase the size of the XML output.
+
+XML_PROGRAMLISTING = YES
+
+#---------------------------------------------------------------------------
+# configuration options for the AutoGen Definitions output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_AUTOGEN_DEF tag is set to YES Doxygen will
+# generate an AutoGen Definitions (see autogen.sf.net) file
+# that captures the structure of the code including all
+# documentation. Note that this feature is still experimental
+# and incomplete at the moment.
+
+GENERATE_AUTOGEN_DEF = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to the Perl module output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_PERLMOD tag is set to YES Doxygen will
+# generate a Perl module file that captures the structure of
+# the code including all documentation. Note that this
+# feature is still experimental and incomplete at the
+# moment.
+
+GENERATE_PERLMOD = NO
+
+# If the PERLMOD_LATEX tag is set to YES Doxygen will generate
+# the necessary Makefile rules, Perl scripts and LaTeX code to be able
+# to generate PDF and DVI output from the Perl module output.
+
+PERLMOD_LATEX = NO
+
+# If the PERLMOD_PRETTY tag is set to YES the Perl module output will be
+# nicely formatted so it can be parsed by a human reader.
+# This is useful
+# if you want to understand what is going on.
+# On the other hand, if this
+# tag is set to NO the size of the Perl module output will be much smaller
+# and Perl will parse it just the same.
+
+PERLMOD_PRETTY = YES
+
+# The names of the make variables in the generated doxyrules.make file
+# are prefixed with the string contained in PERLMOD_MAKEVAR_PREFIX.
+# This is useful so different doxyrules.make files included by the same
+# Makefile don't overwrite each other's variables.
+
+PERLMOD_MAKEVAR_PREFIX =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the preprocessor
+#---------------------------------------------------------------------------
+
+# If the ENABLE_PREPROCESSING tag is set to YES (the default) Doxygen will
+# evaluate all C-preprocessor directives found in the sources and include
+# files.
+
+ENABLE_PREPROCESSING = YES
+
+# If the MACRO_EXPANSION tag is set to YES Doxygen will expand all macro
+# names in the source code. If set to NO (the default) only conditional
+# compilation will be performed. Macro expansion can be done in a controlled
+# way by setting EXPAND_ONLY_PREDEF to YES.
+
+MACRO_EXPANSION = NO
+
+# If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES
+# then the macro expansion is limited to the macros specified with the
+# PREDEFINED and EXPAND_AS_DEFINED tags.
+
+EXPAND_ONLY_PREDEF = NO
+
+# If the SEARCH_INCLUDES tag is set to YES (the default) the includes files
+# pointed to by INCLUDE_PATH will be searched when a #include is found.
+
+SEARCH_INCLUDES = YES
+
+# The INCLUDE_PATH tag can be used to specify one or more directories that
+# contain include files that are not input files but should be processed by
+# the preprocessor.
+
+INCLUDE_PATH =
+
+# You can use the INCLUDE_FILE_PATTERNS tag to specify one or more wildcard
+# patterns (like *.h and *.hpp) to filter out the header-files in the
+# directories. If left blank, the patterns specified with FILE_PATTERNS will
+# be used.
+
+INCLUDE_FILE_PATTERNS =
+
+# The PREDEFINED tag can be used to specify one or more macro names that
+# are defined before the preprocessor is started (similar to the -D option of
+# gcc). The argument of the tag is a list of macros of the form: name
+# or name=definition (no spaces). If the definition and the = are
+# omitted =1 is assumed. To prevent a macro definition from being
+# undefined via #undef or recursively expanded use the := operator
+# instead of the = operator.
+
+PREDEFINED = DOXYGEN
+
+# If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then
+# this tag can be used to specify a list of macro names that should be expanded.
+# The macro definition that is found in the sources will be used.
+# Use the PREDEFINED tag if you want to use a different macro definition that
+# overrules the definition found in the source code.
+
+EXPAND_AS_DEFINED =
+
+# If the SKIP_FUNCTION_MACROS tag is set to YES (the default) then
+# doxygen's preprocessor will remove all references to function-like macros
+# that are alone on a line, have an all uppercase name, and do not end with a
+# semicolon, because these will confuse the parser if not removed.
+
+SKIP_FUNCTION_MACROS = YES
+
+#---------------------------------------------------------------------------
+# Configuration::additions related to external references
+#---------------------------------------------------------------------------
+
+# The TAGFILES option can be used to specify one or more tagfiles.
+# Optionally an initial location of the external documentation
+# can be added for each tagfile. The format of a tag file without
+# this location is as follows:
+#
+# TAGFILES = file1 file2 ...
+# Adding location for the tag files is done as follows:
+#
+# TAGFILES = file1=loc1 "file2 = loc2" ...
+# where "loc1" and "loc2" can be relative or absolute paths or
+# URLs. If a location is present for each tag, the installdox tool
+# does not have to be run to correct the links.
+# Note that each tag file must have a unique name
+# (where the name does NOT include the path)
+# If a tag file is not located in the directory in which doxygen
+# is run, you must also specify the path to the tagfile here.
+
+TAGFILES =
+
+# When a file name is specified after GENERATE_TAGFILE, doxygen will create
+# a tag file that is based on the input files it reads.
+
+GENERATE_TAGFILE =
+
+# If the ALLEXTERNALS tag is set to YES all external classes will be listed
+# in the class index. If set to NO only the inherited external classes
+# will be listed.
+
+ALLEXTERNALS = NO
+
+# If the EXTERNAL_GROUPS tag is set to YES all external groups will be listed
+# in the modules index. If set to NO, only the current project's groups will
+# be listed.
+
+EXTERNAL_GROUPS = YES
+
+# The PERL_PATH should be the absolute path and name of the perl script
+# interpreter (i.e. the result of `which perl').
+
+PERL_PATH = /usr/bin/perl
+
+#---------------------------------------------------------------------------
+# Configuration options related to the dot tool
+#---------------------------------------------------------------------------
+
+# If the CLASS_DIAGRAMS tag is set to YES (the default) Doxygen will
+# generate a inheritance diagram (in HTML, RTF and LaTeX) for classes with base
+# or super classes. Setting the tag to NO turns the diagrams off. Note that
+# this option also works with HAVE_DOT disabled, but it is recommended to
+# install and use dot, since it yields more powerful graphs.
+
+CLASS_DIAGRAMS = YES
+
+# You can define message sequence charts within doxygen comments using the \msc
+# command. Doxygen will then run the mscgen tool (see
+# http://www.mcternan.me.uk/mscgen/) to produce the chart and insert it in the
+# documentation. The MSCGEN_PATH tag allows you to specify the directory where
+# the mscgen tool resides. If left empty the tool is assumed to be found in the
+# default search path.
+
+MSCGEN_PATH =
+
+# If set to YES, the inheritance and collaboration graphs will hide
+# inheritance and usage relations if the target is undocumented
+# or is not a class.
+
+HIDE_UNDOC_RELATIONS = YES
+
+# If you set the HAVE_DOT tag to YES then doxygen will assume the dot tool is
+# available from the path. This tool is part of Graphviz, a graph visualization
+# toolkit from AT&T and Lucent Bell Labs. The other options in this section
+# have no effect if this option is set to NO (the default)
+
+HAVE_DOT = NO
+
+# The DOT_NUM_THREADS specifies the number of dot invocations doxygen is
+# allowed to run in parallel. When set to 0 (the default) doxygen will
+# base this on the number of processors available in the system. You can set it
+# explicitly to a value larger than 0 to get control over the balance
+# between CPU load and processing speed.
+
+DOT_NUM_THREADS = 0
+
+# By default doxygen will use the Helvetica font for all dot files that
+# doxygen generates. When you want a differently looking font you can specify
+# the font name using DOT_FONTNAME. You need to make sure dot is able to find
+# the font, which can be done by putting it in a standard location or by setting
+# the DOTFONTPATH environment variable or by setting DOT_FONTPATH to the
+# directory containing the font.
+
+DOT_FONTNAME = Helvetica
+
+# The DOT_FONTSIZE tag can be used to set the size of the font of dot graphs.
+# The default size is 10pt.
+
+DOT_FONTSIZE = 10
+
+# By default doxygen will tell dot to use the Helvetica font.
+# If you specify a different font using DOT_FONTNAME you can use DOT_FONTPATH to
+# set the path where dot can find it.
+
+DOT_FONTPATH =
+
+# If the CLASS_GRAPH and HAVE_DOT tags are set to YES then doxygen
+# will generate a graph for each documented class showing the direct and
+# indirect inheritance relations. Setting this tag to YES will force the
+# CLASS_DIAGRAMS tag to NO.
+
+CLASS_GRAPH = YES
+
+# If the COLLABORATION_GRAPH and HAVE_DOT tags are set to YES then doxygen
+# will generate a graph for each documented class showing the direct and
+# indirect implementation dependencies (inheritance, containment, and
+# class references variables) of the class with other documented classes.
+
+COLLABORATION_GRAPH = YES
+
+# If the GROUP_GRAPHS and HAVE_DOT tags are set to YES then doxygen
+# will generate a graph for groups, showing the direct groups dependencies
+
+GROUP_GRAPHS = YES
+
+# If the UML_LOOK tag is set to YES doxygen will generate inheritance and
+# collaboration diagrams in a style similar to the OMG's Unified Modeling
+# Language.
+
+UML_LOOK = NO
+
+# If set to YES, the inheritance and collaboration graphs will show the
+# relations between templates and their instances.
+
+TEMPLATE_RELATIONS = NO
+
+# If the ENABLE_PREPROCESSING, SEARCH_INCLUDES, INCLUDE_GRAPH, and HAVE_DOT
+# tags are set to YES then doxygen will generate a graph for each documented
+# file showing the direct and indirect include dependencies of the file with
+# other documented files.
+
+INCLUDE_GRAPH = YES
+
+# If the ENABLE_PREPROCESSING, SEARCH_INCLUDES, INCLUDED_BY_GRAPH, and
+# HAVE_DOT tags are set to YES then doxygen will generate a graph for each
+# documented header file showing the documented files that directly or
+# indirectly include this file.
+
+INCLUDED_BY_GRAPH = YES
+
+# If the CALL_GRAPH and HAVE_DOT options are set to YES then
+# doxygen will generate a call dependency graph for every global function
+# or class method. Note that enabling this option will significantly increase
+# the time of a run. So in most cases it will be better to enable call graphs
+# for selected functions only using the \callgraph command.
+
+CALL_GRAPH = NO
+
+# If the CALLER_GRAPH and HAVE_DOT tags are set to YES then
+# doxygen will generate a caller dependency graph for every global function
+# or class method. Note that enabling this option will significantly increase
+# the time of a run. So in most cases it will be better to enable caller
+# graphs for selected functions only using the \callergraph command.
+
+CALLER_GRAPH = NO
+
+# If the GRAPHICAL_HIERARCHY and HAVE_DOT tags are set to YES then doxygen
+# will generate a graphical hierarchy of all classes instead of a textual one.
+
+GRAPHICAL_HIERARCHY = YES
+
+# If the DIRECTORY_GRAPH, SHOW_DIRECTORIES and HAVE_DOT tags are set to YES
+# then doxygen will show the dependencies a directory has on other directories
+# in a graphical way. The dependency relations are determined by the #include
+# relations between the files in the directories.
+
+DIRECTORY_GRAPH = YES
+
+# The DOT_IMAGE_FORMAT tag can be used to set the image format of the images
+# generated by dot. Possible values are svg, png, jpg, or gif.
+# If left blank png will be used. If you choose svg you need to set
+# HTML_FILE_EXTENSION to xhtml in order to make the SVG files
+# visible in IE 9+ (other browsers do not have this requirement).
+
+DOT_IMAGE_FORMAT = png
+
+# If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
+# enable generation of interactive SVG images that allow zooming and panning.
+# Note that this requires a modern browser other than Internet Explorer.
+# Tested and working are Firefox, Chrome, Safari, and Opera. For IE 9+ you
+# need to set HTML_FILE_EXTENSION to xhtml in order to make the SVG files
+# visible. Older versions of IE do not have SVG support.
+
+INTERACTIVE_SVG = NO
+
+# The tag DOT_PATH can be used to specify the path where the dot tool can be
+# found. If left blank, it is assumed the dot tool can be found in the path.
+
+DOT_PATH =
+
+# The DOTFILE_DIRS tag can be used to specify one or more directories that
+# contain dot files that are included in the documentation (see the
+# \dotfile command).
+
+DOTFILE_DIRS =
+
+# The MSCFILE_DIRS tag can be used to specify one or more directories that
+# contain msc files that are included in the documentation (see the
+# \mscfile command).
+
+MSCFILE_DIRS =
+
+# The DOT_GRAPH_MAX_NODES tag can be used to set the maximum number of
+# nodes that will be shown in the graph. If the number of nodes in a graph
+# becomes larger than this value, doxygen will truncate the graph, which is
+# visualized by representing a node as a red box. Note that doxygen if the
+# number of direct children of the root node in a graph is already larger than
+# DOT_GRAPH_MAX_NODES then the graph will not be shown at all. Also note
+# that the size of a graph can be further restricted by MAX_DOT_GRAPH_DEPTH.
+
+DOT_GRAPH_MAX_NODES = 50
+
+# The MAX_DOT_GRAPH_DEPTH tag can be used to set the maximum depth of the
+# graphs generated by dot. A depth value of 3 means that only nodes reachable
+# from the root by following a path via at most 3 edges will be shown. Nodes
+# that lay further from the root node will be omitted. Note that setting this
+# option to 1 or 2 may greatly reduce the computation time needed for large
+# code bases. Also note that the size of a graph can be further restricted by
+# DOT_GRAPH_MAX_NODES. Using a depth of 0 means no depth restriction.
+
+MAX_DOT_GRAPH_DEPTH = 0
+
+# Set the DOT_TRANSPARENT tag to YES to generate images with a transparent
+# background. This is disabled by default, because dot on Windows does not
+# seem to support this out of the box. Warning: Depending on the platform used,
+# enabling this option may lead to badly anti-aliased labels on the edges of
+# a graph (i.e. they become hard to read).
+
+DOT_TRANSPARENT = NO
+
+# Set the DOT_MULTI_TARGETS tag to YES allow dot to generate multiple output
+# files in one run (i.e. multiple -o and -T options on the command line). This
+# makes dot run faster, but since only newer versions of dot (>1.8.10)
+# support this, this feature is disabled by default.
+
+DOT_MULTI_TARGETS = YES
+
+# If the GENERATE_LEGEND tag is set to YES (the default) Doxygen will
+# generate a legend page explaining the meaning of the various boxes and
+# arrows in the dot generated graphs.
+
+GENERATE_LEGEND = YES
+
+# If the DOT_CLEANUP tag is set to YES (the default) Doxygen will
+# remove the intermediate dot files that are used to generate
+# the various graphs.
+
+DOT_CLEANUP = YES
diff --git a/jni/pjproject-android/.svn/pristine/c5/c5d1820cd0fecc10721dbc1b8b529b04f5228a56.svn-base b/jni/pjproject-android/.svn/pristine/c5/c5d1820cd0fecc10721dbc1b8b529b04f5228a56.svn-base
new file mode 100644
index 0000000..c086b01
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c5d1820cd0fecc10721dbc1b8b529b04f5228a56.svn-base
@@ -0,0 +1,689 @@
+/* $Id$ */
+/*
+ * Copyright (C) 2013 Teluu Inc. (http://www.teluu.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#ifndef __PJSUA2_PERSISTENT_HPP__
+#define __PJSUA2_PERSISTENT_HPP__
+
+/**
+ * @file pjsua2/persistent.hpp
+ * @brief PJSUA2 Persistent Services
+ */
+#include <pjsua2/types.hpp>
+
+#include <string>
+#include <vector>
+
+/** PJSUA2 API is inside pj namespace */
+namespace pj
+{
+
+/**
+ * @defgroup PJSUA2_PERSISTENT Persistent API
+ * @ingroup PJSUA2_Ref
+ * @{
+ * The persistent API provides functionality to read/write data from/to
+ * a document (string or file). The data can be simple data types such
+ * as boolean, number, string, and string arrays, or a user defined object.
+ * Currently the implementation supports reading and writing from/to JSON
+ * document, but the framework allows application to extend the API to
+ * support other document formats.
+ */
+
+using std::string;
+using std::vector;
+
+/* Forward declaration for ContainerNode */
+class ContainerNode;
+
+/**
+ * This is the abstract base class of objects that can be serialized to/from
+ * persistent document.
+ */
+class PersistentObject
+{
+public:
+ /**
+ * Read this object from a container node.
+ *
+ * @param node Container to read values from.
+ */
+ virtual void readObject(const ContainerNode &node) throw(Error) = 0;
+
+ /**
+ * Write this object to a container node.
+ *
+ * @param node Container to write values to.
+ */
+ virtual void writeObject(ContainerNode &node) const throw(Error) = 0;
+};
+
+
+/**
+ * This a the abstract base class for a persistent document. A document
+ * is created either by loading from a string or a file, or by constructing
+ * it manually when writing data to it. The document then can be saved
+ * to either string or to a file. A document contains one root ContainerNode
+ * where all data are stored under.
+ *
+ * Document is read and written serially, hence the order of reading must be
+ * the same as the order of writing. The PersistentDocument class provides
+ * API to read and write to the root node, but for more flexible operations
+ * application can use the ContainerNode methods instead. Indeed the read
+ * and write API in PersistentDocument is just a shorthand which calls the
+ * relevant methods in the ContainerNode. As a tip, normally application only
+ * uses the readObject() and writeObject() methods declared here to read/write
+ * top level objects, and use the macros that are explained in ContainerNode
+ * documentation to read/write more detailed data.
+ */
+class PersistentDocument
+{
+public:
+ /**
+ * Virtual destructor
+ */
+ virtual ~PersistentDocument()
+ {}
+
+ /**
+ * Load this document from a file.
+ *
+ * @param filename The file name.
+ */
+ virtual void loadFile(const string &filename) throw(Error) = 0;
+
+ /**
+ * Load this document from string.
+ *
+ * @param input The string.
+ */
+ virtual void loadString(const string &input) throw(Error) = 0;
+
+ /**
+ * Write this document to a file.
+ *
+ * @param filename The file name.
+ */
+ virtual void saveFile(const string &filename) throw(Error) = 0;
+
+ /**
+ * Write this document to string.
+ *
+ * @return The string document.
+ */
+ virtual string saveString() throw(Error) = 0;
+
+ /**
+ * Get the root container node for this document
+ *
+ * @return The root node.
+ */
+ virtual ContainerNode & getRootContainer() const = 0;
+
+
+ /*
+ * Shorthand functions for reading and writing from/to the root container
+ */
+
+
+ /**
+ * Determine if there is unread element. If yes, then app can use one of
+ * the readXxx() functions to read it.
+ *
+ * @return True if there is.
+ */
+ bool hasUnread() const;
+
+ /**
+ * Get the name of the next unread element. It will throw Error if there
+ * is no more element to read.
+ *
+ * @return The name of the next element .
+ */
+ string unreadName() const throw(Error);
+
+ /**
+ * Read an integer value from the document and return the value.
+ * This will throw Error if the current element is not a number.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ int readInt(const string &name="") const throw(Error);
+
+ /**
+ * Read a float value from the document and return the value.
+ * This will throw Error if the current element is not a number.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ float readNumber(const string &name="") const throw(Error);
+
+ /**
+ * Read a boolean value from the container and return the value.
+ * This will throw Error if the current element is not a boolean.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ bool readBool(const string &name="") const throw(Error);
+
+ /**
+ * Read a string value from the container and return the value.
+ * This will throw Error if the current element is not a string.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ string readString(const string &name="") const throw(Error);
+
+ /**
+ * Read a string array from the container. This will throw Error
+ * if the current element is not a string array. The read position
+ * will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ StringVector readStringVector(const string &name="") const
+ throw(Error);
+
+ /**
+ * Read the specified object from the container. This is equal to
+ * calling PersistentObject.readObject(ContainerNode);
+ *
+ * @param obj The object to read.
+ */
+ void readObject(PersistentObject &obj) const throw(Error);
+
+ /**
+ * Read a container from the container. This will throw Error if the
+ * current element is not an object. The read position will be advanced
+ * to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return Container object.
+ */
+ ContainerNode readContainer(const string &name="") const
+ throw(Error);
+
+ /**
+ * Read array container from the container. This will throw Error if the
+ * current element is not an array. The read position will be advanced
+ * to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return Container object.
+ */
+ ContainerNode readArray(const string &name="") const
+ throw(Error);
+
+ /**
+ * Write a number value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param num The value to be written.
+ */
+ void writeNumber(const string &name,
+ float num) throw(Error);
+
+ /**
+ * Write a number value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param num The value to be written.
+ */
+ void writeInt(const string &name,
+ int num) throw(Error);
+
+ /**
+ * Write a boolean value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param value The value to be written.
+ */
+ void writeBool(const string &name,
+ bool value) throw(Error);
+
+ /**
+ * Write a string value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param value The value to be written.
+ */
+ void writeString(const string &name,
+ const string &value) throw(Error);
+
+ /**
+ * Write string vector to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param arr The vector to be written.
+ */
+ void writeStringVector(const string &name,
+ const StringVector &arr)
+ throw(Error);
+
+ /**
+ * Write an object to the container. This is equal to calling
+ * PersistentObject.writeObject(ContainerNode);
+ *
+ * @param obj The object to be written
+ */
+ void writeObject(const PersistentObject &obj) throw(Error);
+
+ /**
+ * Create and write an empty Object node that can be used as parent
+ * for subsequent write operations.
+ *
+ * @param name The name for the new container in the container.
+ *
+ * @return A sub-container.
+ */
+ ContainerNode writeNewContainer(const string &name)
+ throw(Error);
+
+ /**
+ * Create and write an empty array node that can be used as parent
+ * for subsequent write operations.
+ *
+ * @param name The name for the array.
+ *
+ * @return A sub-container.
+ */
+ ContainerNode writeNewArray(const string &name)
+ throw(Error);
+};
+
+
+/**
+ * Forward declaration of container_node_op.
+ */
+struct container_node_op;
+
+
+/**
+ * Internal data for ContainerNode. See ContainerNode implementation notes
+ * for more info.
+ */
+struct container_node_internal_data
+{
+ void *doc; /**< The document. */
+ void *data1; /**< Internal data 1 */
+ void *data2; /**< Internal data 2 */
+};
+
+/**
+ * A container node is a placeholder for storing other data elements, which
+ * could be boolean, number, string, array of strings, or another container.
+ * Each data in the container is basically a name/value pair, with a type
+ * internally associated with it so that written data can be read in the
+ * correct type. Data is read and written serially, hence the order of
+ * reading must be the same as the order of writing.
+ *
+ * Application can read data from it by using the various read methods, and
+ * write data to it using the various write methods. Alternatively, it
+ * may be more convenient to use the provided macros below to read and write
+ * the data, because these macros set the name automatically:
+ * - NODE_READ_BOOL(node,item)
+ * - NODE_READ_UNSIGNED(node,item)
+ * - NODE_READ_INT(node,item)
+ * - NODE_READ_FLOAT(node,item)
+ * - NODE_READ_NUM_T(node,type,item)
+ * - NODE_READ_STRING(node,item)
+ * - NODE_READ_STRINGV(node,item)
+ * - NODE_READ_OBJ(node,item)
+ * - NODE_WRITE_BOOL(node,item)
+ * - NODE_WRITE_UNSIGNED(node,item)
+ * - NODE_WRITE_INT(node,item)
+ * - NODE_WRITE_FLOAT(node,item)
+ * - NODE_WRITE_NUM_T(node,type,item)
+ * - NODE_WRITE_STRING(node,item)
+ * - NODE_WRITE_STRINGV(node,item)
+ * - NODE_WRITE_OBJ(node,item)
+ *
+ * Implementation notes:
+ *
+ * The ContainerNode class is subclass-able, but not in the usual C++ way.
+ * With the usual C++ inheritance, some methods will be made pure virtual
+ * and must be implemented by the actual class. However, doing so will
+ * require dynamic instantiation of the ContainerNode class, which means
+ * we will need to pass around the class as pointer, for example as the
+ * return value of readContainer() and writeNewContainer() methods. Then
+ * we will need to establish who needs or how to delete these objects, or
+ * use shared pointer mechanism, each of which is considered too inconvenient
+ * or complicated for the purpose.
+ *
+ * So hence we use C style "inheritance", where the methods are declared in
+ * container_node_op and the data in container_node_internal_data structures.
+ * An implementation of ContainerNode class will need to set up these members
+ * with values that makes sense to itself. The methods in container_node_op
+ * contains the pointer to the actual implementation of the operation, which
+ * would be specific according to the format of the document. The methods in
+ * this ContainerNode class are just thin wrappers which call the
+ * implementation in the container_node_op structure.
+ *
+ */
+class ContainerNode
+{
+public:
+ /**
+ * Determine if there is unread element. If yes, then app can use one of
+ * the readXxx() functions to read it.
+ */
+ bool hasUnread() const;
+
+ /**
+ * Get the name of the next unread element.
+ */
+ string unreadName() const throw(Error);
+
+ /**
+ * Read an integer value from the document and return the value.
+ * This will throw Error if the current element is not a number.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ int readInt(const string &name="") const throw(Error);
+
+ /**
+ * Read a number value from the document and return the value.
+ * This will throw Error if the current element is not a number.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ float readNumber(const string &name="") const throw(Error);
+
+ /**
+ * Read a boolean value from the container and return the value.
+ * This will throw Error if the current element is not a boolean.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ bool readBool(const string &name="") const throw(Error);
+
+ /**
+ * Read a string value from the container and return the value.
+ * This will throw Error if the current element is not a string.
+ * The read position will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ string readString(const string &name="") const throw(Error);
+
+ /**
+ * Read a string array from the container. This will throw Error
+ * if the current element is not a string array. The read position
+ * will be advanced to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return The value.
+ */
+ StringVector readStringVector(const string &name="") const
+ throw(Error);
+
+ /**
+ * Read the specified object from the container. This is equal to
+ * calling PersistentObject.readObject(ContainerNode);
+ *
+ * @param obj The object to read.
+ */
+ void readObject(PersistentObject &obj) const throw(Error);
+
+ /**
+ * Read a container from the container. This will throw Error if the
+ * current element is not a container. The read position will be advanced
+ * to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return Container object.
+ */
+ ContainerNode readContainer(const string &name="") const
+ throw(Error);
+
+ /**
+ * Read array container from the container. This will throw Error if the
+ * current element is not an array. The read position will be advanced
+ * to the next element.
+ *
+ * @param name If specified, then the function will check if the
+ * name of the next element matches the specified
+ * name and throw Error if it doesn't match.
+ *
+ * @return Container object.
+ */
+ ContainerNode readArray(const string &name="") const
+ throw(Error);
+
+ /**
+ * Write a number value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param num The value to be written.
+ */
+ void writeNumber(const string &name,
+ float num) throw(Error);
+
+ /**
+ * Write a number value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param num The value to be written.
+ */
+ void writeInt(const string &name,
+ int num) throw(Error);
+
+ /**
+ * Write a boolean value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param value The value to be written.
+ */
+ void writeBool(const string &name,
+ bool value) throw(Error);
+
+ /**
+ * Write a string value to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param value The value to be written.
+ */
+ void writeString(const string &name,
+ const string &value) throw(Error);
+
+ /**
+ * Write string vector to the container.
+ *
+ * @param name The name for the value in the container.
+ * @param arr The vector to be written.
+ */
+ void writeStringVector(const string &name,
+ const StringVector &arr)
+ throw(Error);
+
+ /**
+ * Write an object to the container. This is equal to calling
+ * PersistentObject.writeObject(ContainerNode);
+ *
+ * @param obj The object to be written
+ */
+ void writeObject(const PersistentObject &obj) throw(Error);
+
+ /**
+ * Create and write an empty Object node that can be used as parent
+ * for subsequent write operations.
+ *
+ * @param name The name for the new container in the container.
+ *
+ * @return A sub-container.
+ */
+ ContainerNode writeNewContainer(const string &name)
+ throw(Error);
+
+ /**
+ * Create and write an empty array node that can be used as parent
+ * for subsequent write operations.
+ *
+ * @param name The name for the array.
+ *
+ * @return A sub-container.
+ */
+ ContainerNode writeNewArray(const string &name)
+ throw(Error);
+
+public:
+ /* internal data */
+ container_node_op *op; /**< Method table. */
+ container_node_internal_data data; /**< Internal data */
+};
+
+
+/**
+ * Pointer to actual ContainerNode implementation. See ContainerNode
+ * implementation notes for more info.
+ */
+//! @cond Doxygen_Suppress
+struct container_node_op
+{
+ bool (*hasUnread)(const ContainerNode*);
+ string (*unreadName)(const ContainerNode*)
+ throw(Error);
+ float (*readNumber)(const ContainerNode*,
+ const string&)
+ throw(Error);
+ bool (*readBool)(const ContainerNode*,
+ const string&)
+ throw(Error);
+ string (*readString)(const ContainerNode*,
+ const string&)
+ throw(Error);
+ StringVector (*readStringVector)(const ContainerNode*,
+ const string&)
+ throw(Error);
+ ContainerNode (*readContainer)(const ContainerNode*,
+ const string &)
+ throw(Error);
+ ContainerNode (*readArray)(const ContainerNode*,
+ const string &)
+ throw(Error);
+ void (*writeNumber)(ContainerNode*,
+ const string &name,
+ float num)
+ throw(Error);
+ void (*writeBool)(ContainerNode*,
+ const string &name,
+ bool value)
+ throw(Error);
+ void (*writeString)(ContainerNode*,
+ const string &name,
+ const string &value)
+ throw(Error);
+ void (*writeStringVector)(ContainerNode*,
+ const string &name,
+ const StringVector &value)
+ throw(Error);
+ ContainerNode (*writeNewContainer)(ContainerNode*,
+ const string &name)
+ throw(Error);
+ ContainerNode (*writeNewArray)(ContainerNode*,
+ const string &name)
+ throw(Error);
+};
+
+/*
+ * Convenient macros.
+ */
+#define NODE_READ_BOOL(node,item) item = node.readBool(#item)
+#define NODE_READ_UNSIGNED(node,item) item = (unsigned)node.readNumber(#item)
+#define NODE_READ_INT(node,item) item = (int) node.readNumber(#item)
+#define NODE_READ_FLOAT(node,item) item = node.readNumber(#item)
+#define NODE_READ_NUM_T(node,T,item) item = (T)(int)node.readNumber(#item)
+#define NODE_READ_STRING(node,item) item = node.readString(#item)
+#define NODE_READ_STRINGV(node,item) item = node.readStringVector(#item)
+#define NODE_READ_OBJ(node,item) node.readObject(item)
+
+#define NODE_WRITE_BOOL(node,item) node.writeBool(#item, item)
+#define NODE_WRITE_UNSIGNED(node,item) node.writeNumber(#item, (float)item)
+#define NODE_WRITE_INT(node,item) node.writeNumber(#item, (float)item)
+#define NODE_WRITE_NUM_T(node,T,item) node.writeNumber(#item, (float)item)
+#define NODE_WRITE_FLOAT(node,item) node.writeNumber(#item, item)
+#define NODE_WRITE_STRING(node,item) node.writeString(#item, item)
+#define NODE_WRITE_STRINGV(node,item) node.writeStringVector(#item, item)
+#define NODE_WRITE_OBJ(node,item) node.writeObject(item)
+
+//! @endcond
+
+/**
+ * @} PJSUA2
+ */
+
+} // namespace pj
+
+
+
+#endif /* __PJSUA2_PERSISTENT_HPP__ */
diff --git a/jni/pjproject-android/.svn/pristine/c5/c5ed1e2f5b3bc17b9ecf93a800ad491fa24e9920.svn-base b/jni/pjproject-android/.svn/pristine/c5/c5ed1e2f5b3bc17b9ecf93a800ad491fa24e9920.svn-base
new file mode 100644
index 0000000..28ab9ec
--- /dev/null
+++ b/jni/pjproject-android/.svn/pristine/c5/c5ed1e2f5b3bc17b9ecf93a800ad491fa24e9920.svn-base
@@ -0,0 +1,12 @@
+// libresample_dll.cpp : Defines the entry point for the DLL application.
+//
+#include <windows.h>
+
+BOOL APIENTRY DllMain( HANDLE hModule,
+ DWORD ul_reason_for_call,
+ LPVOID lpReserved
+ )
+{
+ return TRUE;
+}
+