1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay (at) cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] */ 56 57 #include <openssl/rc4.h> 58 59 #if defined(OPENSSL_NO_ASM) || \ 60 (!defined(OPENSSL_X86_64) && !defined(OPENSSL_X86)) 61 62 #if defined(OPENSSL_64_BIT) 63 #define RC4_CHUNK uint64_t 64 #elif defined(OPENSSL_32_BIT) 65 #define RC4_CHUNK uint32_t 66 #else 67 #error "Unknown word size" 68 #endif 69 70 71 /* RC4 as implemented from a posting from 72 * Newsgroups: sci.crypt 73 * From: sterndark (at) netcom.com (David Sterndark) 74 * Subject: RC4 Algorithm revealed. 75 * Message-ID: <sternCvKL4B.Hyy (at) netcom.com> 76 * Date: Wed, 14 Sep 1994 06:35:31 GMT */ 77 78 void RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out) { 79 uint32_t *d; 80 uint32_t x, y, tx, ty; 81 size_t i; 82 83 x = key->x; 84 y = key->y; 85 d = key->data; 86 87 #define RC4_STEP \ 88 (x = (x + 1) & 0xff, tx = d[x], y = (tx + y) & 0xff, ty = d[y], d[y] = tx, \ 89 d[x] = ty, (RC4_CHUNK)d[(tx + ty) & 0xff]) 90 91 if ((((size_t)in & (sizeof(RC4_CHUNK) - 1)) | 92 ((size_t)out & (sizeof(RC4_CHUNK) - 1))) == 0) { 93 RC4_CHUNK ichunk, otp; 94 const union { 95 long one; 96 char little; 97 } is_endian = {1}; 98 99 /* I reckon we can afford to implement both endian 100 * cases and to decide which way to take at run-time 101 * because the machine code appears to be very compact 102 * and redundant 1-2KB is perfectly tolerable (i.e. 103 * in case the compiler fails to eliminate it:-). By 104 * suggestion from Terrel Larson <terr (at) terralogic.net> 105 * who also stands for the is_endian union:-) 106 * 107 * Special notes. 108 * 109 * - is_endian is declared automatic as doing otherwise 110 * (declaring static) prevents gcc from eliminating 111 * the redundant code; 112 * - compilers (those I've tried) don't seem to have 113 * problems eliminating either the operators guarded 114 * by "if (sizeof(RC4_CHUNK)==8)" or the condition 115 * expressions themselves so I've got 'em to replace 116 * corresponding #ifdefs from the previous version; 117 * - I chose to let the redundant switch cases when 118 * sizeof(RC4_CHUNK)!=8 be (were also #ifdefed 119 * before); 120 * - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in 121 * [LB]ESHFT guards against "shift is out of range" 122 * warnings when sizeof(RC4_CHUNK)!=8 123 * 124 * <appro (at) fy.chalmers.se> */ 125 if (!is_endian.little) { /* BIG-ENDIAN CASE */ 126 #define BESHFT(c) \ 127 (((sizeof(RC4_CHUNK) - (c) - 1) * 8) & (sizeof(RC4_CHUNK) * 8 - 1)) 128 for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) { 129 ichunk = *(RC4_CHUNK *)in; 130 otp = RC4_STEP << BESHFT(0); 131 otp |= RC4_STEP << BESHFT(1); 132 otp |= RC4_STEP << BESHFT(2); 133 otp |= RC4_STEP << BESHFT(3); 134 #if defined(OPENSSL_64_BIT) 135 otp |= RC4_STEP << BESHFT(4); 136 otp |= RC4_STEP << BESHFT(5); 137 otp |= RC4_STEP << BESHFT(6); 138 otp |= RC4_STEP << BESHFT(7); 139 #endif 140 *(RC4_CHUNK *)out = otp ^ ichunk; 141 in += sizeof(RC4_CHUNK); 142 out += sizeof(RC4_CHUNK); 143 } 144 } else { /* LITTLE-ENDIAN CASE */ 145 #define LESHFT(c) (((c) * 8) & (sizeof(RC4_CHUNK) * 8 - 1)) 146 for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) { 147 ichunk = *(RC4_CHUNK *)in; 148 otp = RC4_STEP; 149 otp |= RC4_STEP << 8; 150 otp |= RC4_STEP << 16; 151 otp |= RC4_STEP << 24; 152 #if defined(OPENSSL_64_BIT) 153 otp |= RC4_STEP << LESHFT(4); 154 otp |= RC4_STEP << LESHFT(5); 155 otp |= RC4_STEP << LESHFT(6); 156 otp |= RC4_STEP << LESHFT(7); 157 #endif 158 *(RC4_CHUNK *)out = otp ^ ichunk; 159 in += sizeof(RC4_CHUNK); 160 out += sizeof(RC4_CHUNK); 161 } 162 } 163 } 164 #define LOOP(in, out) \ 165 x = ((x + 1) & 0xff); \ 166 tx = d[x]; \ 167 y = (tx + y) & 0xff; \ 168 d[x] = ty = d[y]; \ 169 d[y] = tx; \ 170 (out) = d[(tx + ty) & 0xff] ^ (in); 171 172 #ifndef RC4_INDEX 173 #define RC4_LOOP(a, b, i) LOOP(*((a)++), *((b)++)) 174 #else 175 #define RC4_LOOP(a, b, i) LOOP(a[i], b[i]) 176 #endif 177 178 i = len >> 3; 179 if (i) { 180 for (;;) { 181 RC4_LOOP(in, out, 0); 182 RC4_LOOP(in, out, 1); 183 RC4_LOOP(in, out, 2); 184 RC4_LOOP(in, out, 3); 185 RC4_LOOP(in, out, 4); 186 RC4_LOOP(in, out, 5); 187 RC4_LOOP(in, out, 6); 188 RC4_LOOP(in, out, 7); 189 #ifdef RC4_INDEX 190 in += 8; 191 out += 8; 192 #endif 193 if (--i == 0) { 194 break; 195 } 196 } 197 } 198 i = len & 0x07; 199 if (i) { 200 for (;;) { 201 RC4_LOOP(in, out, 0); 202 if (--i == 0) { 203 break; 204 } 205 RC4_LOOP(in, out, 1); 206 if (--i == 0) { 207 break; 208 } 209 RC4_LOOP(in, out, 2); 210 if (--i == 0) { 211 break; 212 } 213 RC4_LOOP(in, out, 3); 214 if (--i == 0) { 215 break; 216 } 217 RC4_LOOP(in, out, 4); 218 if (--i == 0) { 219 break; 220 } 221 RC4_LOOP(in, out, 5); 222 if (--i == 0) { 223 break; 224 } 225 RC4_LOOP(in, out, 6); 226 if (--i == 0) { 227 break; 228 } 229 } 230 } 231 key->x = x; 232 key->y = y; 233 } 234 235 void RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key) { 236 uint32_t tmp; 237 unsigned i, id1, id2; 238 uint32_t *d; 239 240 d = &rc4key->data[0]; 241 rc4key->x = 0; 242 rc4key->y = 0; 243 id1 = id2 = 0; 244 245 #define SK_LOOP(d, n) \ 246 { \ 247 tmp = d[(n)]; \ 248 id2 = (key[id1] + tmp + id2) & 0xff; \ 249 if (++id1 == len) \ 250 id1 = 0; \ 251 d[(n)] = d[id2]; \ 252 d[id2] = tmp; \ 253 } 254 255 for (i = 0; i < 256; i++) { 256 d[i] = i; 257 } 258 for (i = 0; i < 256; i += 4) { 259 SK_LOOP(d, i + 0); 260 SK_LOOP(d, i + 1); 261 SK_LOOP(d, i + 2); 262 SK_LOOP(d, i + 3); 263 } 264 } 265 266 #else 267 268 /* In this case several functions are provided by asm code. However, one cannot 269 * control asm symbol visibility with command line flags and such so they are 270 * always hidden and wrapped by these C functions, which can be so 271 * controlled. */ 272 273 void asm_RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out); 274 void RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out) { 275 asm_RC4(key, len, in, out); 276 } 277 278 void asm_RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key); 279 void RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key) { 280 asm_RC4_set_key(rc4key, len, key); 281 } 282 283 #endif /* OPENSSL_NO_ASM || (!OPENSSL_X86_64 && !OPENSSL_X86) */ 284
