Alexandre Savard | 1b09e31 | 2012-08-07 20:33:29 -0400 | [diff] [blame] | 1 | /* crypto/rc4/rc4_enc.c */ |
| 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * This package is an SSL implementation written |
| 6 | * by Eric Young (eay@cryptsoft.com). |
| 7 | * The implementation was written so as to conform with Netscapes SSL. |
| 8 | * |
| 9 | * This library is free for commercial and non-commercial use as long as |
| 10 | * the following conditions are aheared to. The following conditions |
| 11 | * apply to all code found in this distribution, be it the RC4, RSA, |
| 12 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation |
| 13 | * included with this distribution is covered by the same copyright terms |
| 14 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). |
| 15 | * |
| 16 | * Copyright remains Eric Young's, and as such any Copyright notices in |
| 17 | * the code are not to be removed. |
| 18 | * If this package is used in a product, Eric Young should be given attribution |
| 19 | * as the author of the parts of the library used. |
| 20 | * This can be in the form of a textual message at program startup or |
| 21 | * in documentation (online or textual) provided with the package. |
| 22 | * |
| 23 | * Redistribution and use in source and binary forms, with or without |
| 24 | * modification, are permitted provided that the following conditions |
| 25 | * are met: |
| 26 | * 1. Redistributions of source code must retain the copyright |
| 27 | * notice, this list of conditions and the following disclaimer. |
| 28 | * 2. Redistributions in binary form must reproduce the above copyright |
| 29 | * notice, this list of conditions and the following disclaimer in the |
| 30 | * documentation and/or other materials provided with the distribution. |
| 31 | * 3. All advertising materials mentioning features or use of this software |
| 32 | * must display the following acknowledgement: |
| 33 | * "This product includes cryptographic software written by |
| 34 | * Eric Young (eay@cryptsoft.com)" |
| 35 | * The word 'cryptographic' can be left out if the rouines from the library |
| 36 | * being used are not cryptographic related :-). |
| 37 | * 4. If you include any Windows specific code (or a derivative thereof) from |
| 38 | * the apps directory (application code) you must include an acknowledgement: |
| 39 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
| 40 | * |
| 41 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
| 42 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 43 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 44 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 45 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 46 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 47 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 49 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 50 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 51 | * SUCH DAMAGE. |
| 52 | * |
| 53 | * The licence and distribution terms for any publically available version or |
| 54 | * derivative of this code cannot be changed. i.e. this code cannot simply be |
| 55 | * copied and put under another distribution licence |
| 56 | * [including the GNU Public Licence.] |
| 57 | */ |
| 58 | |
| 59 | #include <openssl/rc4.h> |
| 60 | #include "rc4_locl.h" |
| 61 | |
| 62 | /* RC4 as implemented from a posting from |
| 63 | * Newsgroups: sci.crypt |
| 64 | * From: sterndark@netcom.com (David Sterndark) |
| 65 | * Subject: RC4 Algorithm revealed. |
| 66 | * Message-ID: <sternCvKL4B.Hyy@netcom.com> |
| 67 | * Date: Wed, 14 Sep 1994 06:35:31 GMT |
| 68 | */ |
| 69 | |
| 70 | void RC4(RC4_KEY *key, size_t len, const unsigned char *indata, |
| 71 | unsigned char *outdata) |
| 72 | { |
| 73 | register RC4_INT *d; |
| 74 | register RC4_INT x,y,tx,ty; |
| 75 | size_t i; |
| 76 | |
| 77 | x=key->x; |
| 78 | y=key->y; |
| 79 | d=key->data; |
| 80 | |
| 81 | #if defined(RC4_CHUNK) |
| 82 | /* |
| 83 | * The original reason for implementing this(*) was the fact that |
| 84 | * pre-21164a Alpha CPUs don't have byte load/store instructions |
| 85 | * and e.g. a byte store has to be done with 64-bit load, shift, |
| 86 | * and, or and finally 64-bit store. Peaking data and operating |
| 87 | * at natural word size made it possible to reduce amount of |
| 88 | * instructions as well as to perform early read-ahead without |
| 89 | * suffering from RAW (read-after-write) hazard. This resulted |
| 90 | * in ~40%(**) performance improvement on 21064 box with gcc. |
| 91 | * But it's not only Alpha users who win here:-) Thanks to the |
| 92 | * early-n-wide read-ahead this implementation also exhibits |
| 93 | * >40% speed-up on SPARC and 20-30% on 64-bit MIPS (depending |
| 94 | * on sizeof(RC4_INT)). |
| 95 | * |
| 96 | * (*) "this" means code which recognizes the case when input |
| 97 | * and output pointers appear to be aligned at natural CPU |
| 98 | * word boundary |
| 99 | * (**) i.e. according to 'apps/openssl speed rc4' benchmark, |
| 100 | * crypto/rc4/rc4speed.c exhibits almost 70% speed-up... |
| 101 | * |
| 102 | * Cavets. |
| 103 | * |
| 104 | * - RC4_CHUNK="unsigned long long" should be a #1 choice for |
| 105 | * UltraSPARC. Unfortunately gcc generates very slow code |
| 106 | * (2.5-3 times slower than one generated by Sun's WorkShop |
| 107 | * C) and therefore gcc (at least 2.95 and earlier) should |
| 108 | * always be told that RC4_CHUNK="unsigned long". |
| 109 | * |
| 110 | * <appro@fy.chalmers.se> |
| 111 | */ |
| 112 | |
| 113 | # define RC4_STEP ( \ |
| 114 | x=(x+1) &0xff, \ |
| 115 | tx=d[x], \ |
| 116 | y=(tx+y)&0xff, \ |
| 117 | ty=d[y], \ |
| 118 | d[y]=tx, \ |
| 119 | d[x]=ty, \ |
| 120 | (RC4_CHUNK)d[(tx+ty)&0xff]\ |
| 121 | ) |
| 122 | |
| 123 | if ( ( ((size_t)indata & (sizeof(RC4_CHUNK)-1)) | |
| 124 | ((size_t)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0 ) |
| 125 | { |
| 126 | RC4_CHUNK ichunk,otp; |
| 127 | const union { long one; char little; } is_endian = {1}; |
| 128 | |
| 129 | /* |
| 130 | * I reckon we can afford to implement both endian |
| 131 | * cases and to decide which way to take at run-time |
| 132 | * because the machine code appears to be very compact |
| 133 | * and redundant 1-2KB is perfectly tolerable (i.e. |
| 134 | * in case the compiler fails to eliminate it:-). By |
| 135 | * suggestion from Terrel Larson <terr@terralogic.net> |
| 136 | * who also stands for the is_endian union:-) |
| 137 | * |
| 138 | * Special notes. |
| 139 | * |
| 140 | * - is_endian is declared automatic as doing otherwise |
| 141 | * (declaring static) prevents gcc from eliminating |
| 142 | * the redundant code; |
| 143 | * - compilers (those I've tried) don't seem to have |
| 144 | * problems eliminating either the operators guarded |
| 145 | * by "if (sizeof(RC4_CHUNK)==8)" or the condition |
| 146 | * expressions themselves so I've got 'em to replace |
| 147 | * corresponding #ifdefs from the previous version; |
| 148 | * - I chose to let the redundant switch cases when |
| 149 | * sizeof(RC4_CHUNK)!=8 be (were also #ifdefed |
| 150 | * before); |
| 151 | * - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in |
| 152 | * [LB]ESHFT guards against "shift is out of range" |
| 153 | * warnings when sizeof(RC4_CHUNK)!=8 |
| 154 | * |
| 155 | * <appro@fy.chalmers.se> |
| 156 | */ |
| 157 | if (!is_endian.little) |
| 158 | { /* BIG-ENDIAN CASE */ |
| 159 | # define BESHFT(c) (((sizeof(RC4_CHUNK)-(c)-1)*8)&(sizeof(RC4_CHUNK)*8-1)) |
| 160 | for (;len&(0-sizeof(RC4_CHUNK));len-=sizeof(RC4_CHUNK)) |
| 161 | { |
| 162 | ichunk = *(RC4_CHUNK *)indata; |
| 163 | otp = RC4_STEP<<BESHFT(0); |
| 164 | otp |= RC4_STEP<<BESHFT(1); |
| 165 | otp |= RC4_STEP<<BESHFT(2); |
| 166 | otp |= RC4_STEP<<BESHFT(3); |
| 167 | if (sizeof(RC4_CHUNK)==8) |
| 168 | { |
| 169 | otp |= RC4_STEP<<BESHFT(4); |
| 170 | otp |= RC4_STEP<<BESHFT(5); |
| 171 | otp |= RC4_STEP<<BESHFT(6); |
| 172 | otp |= RC4_STEP<<BESHFT(7); |
| 173 | } |
| 174 | *(RC4_CHUNK *)outdata = otp^ichunk; |
| 175 | indata += sizeof(RC4_CHUNK); |
| 176 | outdata += sizeof(RC4_CHUNK); |
| 177 | } |
| 178 | if (len) |
| 179 | { |
| 180 | RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk; |
| 181 | |
| 182 | ichunk = *(RC4_CHUNK *)indata; |
| 183 | ochunk = *(RC4_CHUNK *)outdata; |
| 184 | otp = 0; |
| 185 | i = BESHFT(0); |
| 186 | mask <<= (sizeof(RC4_CHUNK)-len)<<3; |
| 187 | switch (len&(sizeof(RC4_CHUNK)-1)) |
| 188 | { |
| 189 | case 7: otp = RC4_STEP<<i, i-=8; |
| 190 | case 6: otp |= RC4_STEP<<i, i-=8; |
| 191 | case 5: otp |= RC4_STEP<<i, i-=8; |
| 192 | case 4: otp |= RC4_STEP<<i, i-=8; |
| 193 | case 3: otp |= RC4_STEP<<i, i-=8; |
| 194 | case 2: otp |= RC4_STEP<<i, i-=8; |
| 195 | case 1: otp |= RC4_STEP<<i, i-=8; |
| 196 | case 0: ; /* |
| 197 | * it's never the case, |
| 198 | * but it has to be here |
| 199 | * for ultrix? |
| 200 | */ |
| 201 | } |
| 202 | ochunk &= ~mask; |
| 203 | ochunk |= (otp^ichunk) & mask; |
| 204 | *(RC4_CHUNK *)outdata = ochunk; |
| 205 | } |
| 206 | key->x=x; |
| 207 | key->y=y; |
| 208 | return; |
| 209 | } |
| 210 | else |
| 211 | { /* LITTLE-ENDIAN CASE */ |
| 212 | # define LESHFT(c) (((c)*8)&(sizeof(RC4_CHUNK)*8-1)) |
| 213 | for (;len&(0-sizeof(RC4_CHUNK));len-=sizeof(RC4_CHUNK)) |
| 214 | { |
| 215 | ichunk = *(RC4_CHUNK *)indata; |
| 216 | otp = RC4_STEP; |
| 217 | otp |= RC4_STEP<<8; |
| 218 | otp |= RC4_STEP<<16; |
| 219 | otp |= RC4_STEP<<24; |
| 220 | if (sizeof(RC4_CHUNK)==8) |
| 221 | { |
| 222 | otp |= RC4_STEP<<LESHFT(4); |
| 223 | otp |= RC4_STEP<<LESHFT(5); |
| 224 | otp |= RC4_STEP<<LESHFT(6); |
| 225 | otp |= RC4_STEP<<LESHFT(7); |
| 226 | } |
| 227 | *(RC4_CHUNK *)outdata = otp^ichunk; |
| 228 | indata += sizeof(RC4_CHUNK); |
| 229 | outdata += sizeof(RC4_CHUNK); |
| 230 | } |
| 231 | if (len) |
| 232 | { |
| 233 | RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk; |
| 234 | |
| 235 | ichunk = *(RC4_CHUNK *)indata; |
| 236 | ochunk = *(RC4_CHUNK *)outdata; |
| 237 | otp = 0; |
| 238 | i = 0; |
| 239 | mask >>= (sizeof(RC4_CHUNK)-len)<<3; |
| 240 | switch (len&(sizeof(RC4_CHUNK)-1)) |
| 241 | { |
| 242 | case 7: otp = RC4_STEP, i+=8; |
| 243 | case 6: otp |= RC4_STEP<<i, i+=8; |
| 244 | case 5: otp |= RC4_STEP<<i, i+=8; |
| 245 | case 4: otp |= RC4_STEP<<i, i+=8; |
| 246 | case 3: otp |= RC4_STEP<<i, i+=8; |
| 247 | case 2: otp |= RC4_STEP<<i, i+=8; |
| 248 | case 1: otp |= RC4_STEP<<i, i+=8; |
| 249 | case 0: ; /* |
| 250 | * it's never the case, |
| 251 | * but it has to be here |
| 252 | * for ultrix? |
| 253 | */ |
| 254 | } |
| 255 | ochunk &= ~mask; |
| 256 | ochunk |= (otp^ichunk) & mask; |
| 257 | *(RC4_CHUNK *)outdata = ochunk; |
| 258 | } |
| 259 | key->x=x; |
| 260 | key->y=y; |
| 261 | return; |
| 262 | } |
| 263 | } |
| 264 | #endif |
| 265 | #define LOOP(in,out) \ |
| 266 | x=((x+1)&0xff); \ |
| 267 | tx=d[x]; \ |
| 268 | y=(tx+y)&0xff; \ |
| 269 | d[x]=ty=d[y]; \ |
| 270 | d[y]=tx; \ |
| 271 | (out) = d[(tx+ty)&0xff]^ (in); |
| 272 | |
| 273 | #ifndef RC4_INDEX |
| 274 | #define RC4_LOOP(a,b,i) LOOP(*((a)++),*((b)++)) |
| 275 | #else |
| 276 | #define RC4_LOOP(a,b,i) LOOP(a[i],b[i]) |
| 277 | #endif |
| 278 | |
| 279 | i=len>>3; |
| 280 | if (i) |
| 281 | { |
| 282 | for (;;) |
| 283 | { |
| 284 | RC4_LOOP(indata,outdata,0); |
| 285 | RC4_LOOP(indata,outdata,1); |
| 286 | RC4_LOOP(indata,outdata,2); |
| 287 | RC4_LOOP(indata,outdata,3); |
| 288 | RC4_LOOP(indata,outdata,4); |
| 289 | RC4_LOOP(indata,outdata,5); |
| 290 | RC4_LOOP(indata,outdata,6); |
| 291 | RC4_LOOP(indata,outdata,7); |
| 292 | #ifdef RC4_INDEX |
| 293 | indata+=8; |
| 294 | outdata+=8; |
| 295 | #endif |
| 296 | if (--i == 0) break; |
| 297 | } |
| 298 | } |
| 299 | i=len&0x07; |
| 300 | if (i) |
| 301 | { |
| 302 | for (;;) |
| 303 | { |
| 304 | RC4_LOOP(indata,outdata,0); if (--i == 0) break; |
| 305 | RC4_LOOP(indata,outdata,1); if (--i == 0) break; |
| 306 | RC4_LOOP(indata,outdata,2); if (--i == 0) break; |
| 307 | RC4_LOOP(indata,outdata,3); if (--i == 0) break; |
| 308 | RC4_LOOP(indata,outdata,4); if (--i == 0) break; |
| 309 | RC4_LOOP(indata,outdata,5); if (--i == 0) break; |
| 310 | RC4_LOOP(indata,outdata,6); if (--i == 0) break; |
| 311 | } |
| 312 | } |
| 313 | key->x=x; |
| 314 | key->y=y; |
| 315 | } |