1 /* crypto/rc4/rc4_enc.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
59 #include <openssl/rc4.h>
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
70 void RC4(RC4_KEY *key, unsigned long len, const unsigned char *indata,
71 unsigned char *outdata)
74 register RC4_INT x,y,tx,ty;
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));
85 #if defined(RC4_CHUNK)
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)).
100 * (*) "this" means code which recognizes the case when input
101 * and output pointers appear to be aligned at natural CPU
103 * (**) i.e. according to 'apps/openssl speed rc4' benchmark,
104 * crypto/rc4/rc4speed.c exhibits almost 70% speed-up...
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".
114 * <appro@fy.chalmers.se>
117 # define RC4_STEP ( \
124 (RC4_CHUNK)d[(tx+ty)&0xff]\
127 if ( ( ((unsigned long)indata & (sizeof(RC4_CHUNK)-1)) |
128 ((unsigned long)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0 )
130 RC4_CHUNK ichunk,otp;
131 const union { long one; char little; } is_endian = {1};
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:-)
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
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
159 * <appro@fy.chalmers.se>
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))
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)
173 otp |= RC4_STEP<<BESHFT(4);
174 otp |= RC4_STEP<<BESHFT(5);
175 otp |= RC4_STEP<<BESHFT(6);
176 otp |= RC4_STEP<<BESHFT(7);
178 *(RC4_CHUNK *)outdata = otp^ichunk;
179 indata += sizeof(RC4_CHUNK);
180 outdata += sizeof(RC4_CHUNK);
184 RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;
186 ichunk = *(RC4_CHUNK *)indata;
187 ochunk = *(RC4_CHUNK *)outdata;
190 mask <<= (sizeof(RC4_CHUNK)-len)<<3;
191 switch (len&(sizeof(RC4_CHUNK)-1))
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;
201 * it's never the case,
202 * but it has to be here
207 ochunk |= (otp^ichunk) & mask;
208 *(RC4_CHUNK *)outdata = ochunk;
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))
219 ichunk = *(RC4_CHUNK *)indata;
224 if (sizeof(RC4_CHUNK)==8)
226 otp |= RC4_STEP<<LESHFT(4);
227 otp |= RC4_STEP<<LESHFT(5);
228 otp |= RC4_STEP<<LESHFT(6);
229 otp |= RC4_STEP<<LESHFT(7);
231 *(RC4_CHUNK *)outdata = otp^ichunk;
232 indata += sizeof(RC4_CHUNK);
233 outdata += sizeof(RC4_CHUNK);
237 RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;
239 ichunk = *(RC4_CHUNK *)indata;
240 ochunk = *(RC4_CHUNK *)outdata;
243 mask >>= (sizeof(RC4_CHUNK)-len)<<3;
244 switch (len&(sizeof(RC4_CHUNK)-1))
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;
254 * it's never the case,
255 * but it has to be here
260 ochunk |= (otp^ichunk) & mask;
261 *(RC4_CHUNK *)outdata = ochunk;
269 #define LOOP(in,out) \
275 (out) = d[(tx+ty)&0xff]^ (in);
278 #define RC4_LOOP(a,b,i) LOOP(*((a)++),*((b)++))
280 #define RC4_LOOP(a,b,i) LOOP(a[i],b[i])
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);
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;