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 } 316