* #35924 (zrtp): switch to libzrtpcpp
diff --git a/jni/libzrtp/sources/zrtp/crypto/skein256.h b/jni/libzrtp/sources/zrtp/crypto/skein256.h
new file mode 100644
index 0000000..6d4e722
--- /dev/null
+++ b/jni/libzrtp/sources/zrtp/crypto/skein256.h
@@ -0,0 +1,146 @@
+/*
+ Copyright (C) 2013 Werner Dittmann
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation, either version 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * Functions to compute Skein256 digest.
+ *
+ * @author: Werner Dittmann <Werner.Dittmann@t-online.de>
+ */
+
+#ifndef _SKEIN256_H
+#define _SKEIN256_H
+
+/**
+ * @file skein256.h
+ * @brief Functions that provide Skein256 support
+ *
+ * @ingroup GNU_ZRTP
+ * @{
+ */
+
+#include <stdint.h>
+
+#ifndef SKEIN256_DIGEST_LENGTH
+#define SKEIN256_DIGEST_LENGTH 32
+#endif
+#define SKEIN_SIZE Skein512
+
+
+/**
+ * Compute Skein256 digest.
+ *
+ * This functions takes one data chunk and computes its Skein256 digest. This
+ * function creates and deletes an own Skein256 context to perform the Skein256
+ * operations.
+ *
+ * @param data
+ * Points to the data chunk.
+ * @param data_length
+ * Length of the data in bytes
+ * @param digest
+ * Points to a buffer that receives the computed digest. This
+ * buffer must have a size of at least 32 bytes (Skein256_DIGEST_LENGTH).
+ */
+void skein256(unsigned char *data,
+ unsigned int data_length,
+ unsigned char *digest);
+
+/**
+ * Compute Skein256 digest over several data cunks.
+ *
+ * This functions takes several data chunks and computes the Skein256 digest.
+ * This function creates and deletes an own Skein256 context to perform the
+ * Skein256 operations.
+ *
+ * @param data
+ * Points to an array of pointers that point to the data chunks. A NULL
+ * pointer in an array element terminates the data chunks.
+ * @param data_length
+ * Points to an array of integers that hold the length of each data chunk.
+ * @param digest
+ * Points to a buffer that receives the computed digest. This
+ * buffer must have a size of at least 32 bytes (Skein256_DIGEST_LENGTH).
+ */
+void skein256(unsigned char *data[],
+ unsigned int data_length[],
+ unsigned char *digest);
+/**
+ * Create and initialize a Skein256 context.
+ *
+ * An application uses this context to hash several data into one Skein256
+ * digest. See also skein256Ctx(...) and closeSha256Context(...).
+ *
+ * @return Returns a pointer to the initialized Skein256 context
+ */
+void* createSkein256Context();
+
+/**
+ * Compute a digest and close the SHa256 digest.
+ *
+ * An application uses this function to compute the Skein256 digest and to
+ * close the Skein256 context.
+ *
+ * @param ctx
+ * Points to the Skein256 context.
+ * @param digest
+ * If this pointer is not NULL then it must point to a byte array that
+ * is big enough to hold the Skein256 digest (256 bit = 32 Bytes). If this
+ * pointer is NULL then the functions does not compute the digest but
+ * closes the context only. The context cannot be used anymore.
+ */
+void closeSkein256Context(void* ctx,
+ unsigned char* digest);
+
+/**
+ * Update the Skein256 context with data.
+ *
+ * This functions updates the Skein256 context with some data.
+ * See also CloseSha256Context(...) how to get the digest.
+ *
+ * @param ctx
+ * Points to the Skein256 context.
+ * @param data
+ * Points to the data to update the context.
+ * @param dataLength
+ * The length of the data in bytes.
+ */
+void skein256Ctx(void* ctx, unsigned char* data,
+ unsigned int dataLength);
+
+/**
+ * Update the Skein256 context with several data chunks.
+ *
+ * This functions updates the Skein256 context with some data.
+ * See also CloseSha256Context(...) how to get the digest.
+ *
+ * @param ctx
+ * Points to the Skein256 context.
+ * @param dataChunks
+ * Points to an array of pointers that point to the data chunks. A NULL
+ * pointer in an array element terminates the data chunks.
+ * @param dataChunkLength
+ * Points to an array of integers that hold the length of each data chunk.
+ *
+ */
+void skein256Ctx(void* ctx, unsigned char* dataChunks[],
+ unsigned int dataChunkLength[]);
+
+/**
+ * @}
+ */
+#endif
+