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 70void RC4(RC4_KEY *key, unsigned long len, const unsigned char *indata, 71 unsigned char *outdata) 72 { 73 register RC4_INT *d; 74 register RC4_INT x,y,tx,ty; 75 int i; 76 77 x=key->x; 78 y=key->y; 79 d=key->data; 80#if defined(__ia64) || defined(__ia64__) || defined(_M_IA64) 81 /* see crypto/rc4/asm/rc4-ia64.S for further details... */ 82 d=(RC4_INT *)(((size_t)(d+255))&~(sizeof(key->data)-1)); 83#endif 84 85#if defined(RC4_CHUNK) 86 /* 87 * The original reason for implementing this(*) was the fact that 88 * pre-21164a Alpha CPUs don't have byte load/store instructions 89 * and e.g. a byte store has to be done with 64-bit load, shift, 90 * and, or and finally 64-bit store. Peaking data and operating 91 * at natural word size made it possible to reduce amount of 92 * instructions as well as to perform early read-ahead without 93 * suffering from RAW (read-after-write) hazard. This resulted 94 * in ~40%(**) performance improvement on 21064 box with gcc. 95 * But it's not only Alpha users who win here:-) Thanks to the 96 * early-n-wide read-ahead this implementation also exhibits 97 * >40% speed-up on SPARC and 20-30% on 64-bit MIPS (depending 98 * on sizeof(RC4_INT)). 99 * 100 * (*) "this" means code which recognizes the case when input 101 * and output pointers appear to be aligned at natural CPU 102 * word boundary 103 * (**) i.e. according to 'apps/openssl speed rc4' benchmark, 104 * crypto/rc4/rc4speed.c exhibits almost 70% speed-up... 105 * 106 * Cavets. 107 * 108 * - RC4_CHUNK="unsigned long long" should be a #1 choice for 109 * UltraSPARC. Unfortunately gcc generates very slow code 110 * (2.5-3 times slower than one generated by Sun's WorkShop 111 * C) and therefore gcc (at least 2.95 and earlier) should 112 * always be told that RC4_CHUNK="unsigned long". 113 * 114 * <appro@fy.chalmers.se> 115 */ 116 117# define RC4_STEP ( \ 118 x=(x+1) &0xff, \ 119 tx=d[x], \ 120 y=(tx+y)&0xff, \ 121 ty=d[y], \ 122 d[y]=tx, \ 123 d[x]=ty, \ 124 (RC4_CHUNK)d[(tx+ty)&0xff]\ 125 ) 126 127 if ( ( ((unsigned long)indata & (sizeof(RC4_CHUNK)-1)) | 128 ((unsigned long)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0 ) 129 { 130 RC4_CHUNK ichunk,otp; 131 const union { long one; char little; } is_endian = {1}; 132 133 /* 134 * I reckon we can afford to implement both endian 135 * cases and to decide which way to take at run-time 136 * because the machine code appears to be very compact 137 * and redundant 1-2KB is perfectly tolerable (i.e. 138 * in case the compiler fails to eliminate it:-). By 139 * suggestion from Terrel Larson <terr@terralogic.net> 140 * who also stands for the is_endian union:-) 141 * 142 * Special notes. 143 * 144 * - is_endian is declared automatic as doing otherwise 145 * (declaring static) prevents gcc from eliminating 146 * the redundant code; 147 * - compilers (those I've tried) don't seem to have 148 * problems eliminating either the operators guarded 149 * by "if (sizeof(RC4_CHUNK)==8)" or the condition 150 * expressions themselves so I've got 'em to replace 151 * corresponding #ifdefs from the previous version; 152 * - I chose to let the redundant switch cases when 153 * sizeof(RC4_CHUNK)!=8 be (were also #ifdefed 154 * before); 155 * - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in 156 * [LB]ESHFT guards against "shift is out of range" 157 * warnings when sizeof(RC4_CHUNK)!=8 158 * 159 * <appro@fy.chalmers.se> 160 */ 161 if (!is_endian.little) 162 { /* BIG-ENDIAN CASE */ 163# define BESHFT(c) (((sizeof(RC4_CHUNK)-(c)-1)*8)&(sizeof(RC4_CHUNK)*8-1)) 164 for (;len&-sizeof(RC4_CHUNK);len-=sizeof(RC4_CHUNK)) 165 { 166 ichunk = *(RC4_CHUNK *)indata; 167 otp = RC4_STEP<<BESHFT(0); 168 otp |= RC4_STEP<<BESHFT(1); 169 otp |= RC4_STEP<<BESHFT(2); 170 otp |= RC4_STEP<<BESHFT(3); 171 if (sizeof(RC4_CHUNK)==8) 172 { 173 otp |= RC4_STEP<<BESHFT(4); 174 otp |= RC4_STEP<<BESHFT(5); 175 otp |= RC4_STEP<<BESHFT(6); 176 otp |= RC4_STEP<<BESHFT(7); 177 } 178 *(RC4_CHUNK *)outdata = otp^ichunk; 179 indata += sizeof(RC4_CHUNK); 180 outdata += sizeof(RC4_CHUNK); 181 } 182 if (len) 183 { 184 RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk; 185 186 ichunk = *(RC4_CHUNK *)indata; 187 ochunk = *(RC4_CHUNK *)outdata; 188 otp = 0; 189 i = BESHFT(0); 190 mask <<= (sizeof(RC4_CHUNK)-len)<<3; 191 switch (len&(sizeof(RC4_CHUNK)-1)) 192 { 193 case 7: otp = RC4_STEP<<i, i-=8; 194 case 6: otp |= RC4_STEP<<i, i-=8; 195 case 5: otp |= RC4_STEP<<i, i-=8; 196 case 4: otp |= RC4_STEP<<i, i-=8; 197 case 3: otp |= RC4_STEP<<i, i-=8; 198 case 2: otp |= RC4_STEP<<i, i-=8; 199 case 1: otp |= RC4_STEP<<i, i-=8; 200 case 0: ; /* 201 * it's never the case, 202 * but it has to be here 203 * for ultrix? 204 */ 205 } 206 ochunk &= ~mask; 207 ochunk |= (otp^ichunk) & mask; 208 *(RC4_CHUNK *)outdata = ochunk; 209 } 210 key->x=x; 211 key->y=y; 212 return; 213 } 214 else 215 { /* LITTLE-ENDIAN CASE */ 216# define LESHFT(c) (((c)*8)&(sizeof(RC4_CHUNK)*8-1)) 217 for (;len&-sizeof(RC4_CHUNK);len-=sizeof(RC4_CHUNK)) 218 { 219 ichunk = *(RC4_CHUNK *)indata; 220 otp = RC4_STEP; 221 otp |= RC4_STEP<<8; 222 otp |= RC4_STEP<<16; 223 otp |= RC4_STEP<<24; 224 if (sizeof(RC4_CHUNK)==8) 225 { 226 otp |= RC4_STEP<<LESHFT(4); 227 otp |= RC4_STEP<<LESHFT(5); 228 otp |= RC4_STEP<<LESHFT(6); 229 otp |= RC4_STEP<<LESHFT(7); 230 } 231 *(RC4_CHUNK *)outdata = otp^ichunk; 232 indata += sizeof(RC4_CHUNK); 233 outdata += sizeof(RC4_CHUNK); 234 } 235 if (len) 236 { 237 RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk; 238 239 ichunk = *(RC4_CHUNK *)indata; 240 ochunk = *(RC4_CHUNK *)outdata; 241 otp = 0; 242 i = 0; 243 mask >>= (sizeof(RC4_CHUNK)-len)<<3; 244 switch (len&(sizeof(RC4_CHUNK)-1)) 245 { 246 case 7: otp = RC4_STEP, i+=8; 247 case 6: otp |= RC4_STEP<<i, i+=8; 248 case 5: otp |= RC4_STEP<<i, i+=8; 249 case 4: otp |= RC4_STEP<<i, i+=8; 250 case 3: otp |= RC4_STEP<<i, i+=8; 251 case 2: otp |= RC4_STEP<<i, i+=8; 252 case 1: otp |= RC4_STEP<<i, i+=8; 253 case 0: ; /* 254 * it's never the case, 255 * but it has to be here 256 * for ultrix? 257 */ 258 } 259 ochunk &= ~mask; 260 ochunk |= (otp^ichunk) & mask; 261 *(RC4_CHUNK *)outdata = ochunk; 262 } 263 key->x=x; 264 key->y=y; 265 return; 266 } 267 } 268#endif 269#define LOOP(in,out) \ 270 x=((x+1)&0xff); \ 271 tx=d[x]; \ 272 y=(tx+y)&0xff; \ 273 d[x]=ty=d[y]; \ 274 d[y]=tx; \ 275 (out) = d[(tx+ty)&0xff]^ (in); 276 277#ifndef RC4_INDEX 278#define RC4_LOOP(a,b,i) LOOP(*((a)++),*((b)++)) 279#else 280#define RC4_LOOP(a,b,i) LOOP(a[i],b[i]) 281#endif 282 283 i=(int)(len>>3L); 284 if (i) 285 { 286 for (;;) 287 { 288 RC4_LOOP(indata,outdata,0); 289 RC4_LOOP(indata,outdata,1); 290 RC4_LOOP(indata,outdata,2); 291 RC4_LOOP(indata,outdata,3); 292 RC4_LOOP(indata,outdata,4); 293 RC4_LOOP(indata,outdata,5); 294 RC4_LOOP(indata,outdata,6); 295 RC4_LOOP(indata,outdata,7); 296#ifdef RC4_INDEX 297 indata+=8; 298 outdata+=8; 299#endif 300 if (--i == 0) break; 301 } 302 } 303 i=(int)len&0x07; 304 if (i) 305 { 306 for (;;) 307 { 308 RC4_LOOP(indata,outdata,0); if (--i == 0) break; 309 RC4_LOOP(indata,outdata,1); if (--i == 0) break; 310 RC4_LOOP(indata,outdata,2); if (--i == 0) break; 311 RC4_LOOP(indata,outdata,3); if (--i == 0) break; 312 RC4_LOOP(indata,outdata,4); if (--i == 0) break; 313 RC4_LOOP(indata,outdata,5); if (--i == 0) break; 314 RC4_LOOP(indata,outdata,6); if (--i == 0) break; 315 } 316 } 317 key->x=x; 318 key->y=y; 319 } 320