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
RC4(RC4_KEY * key,unsigned long len,const unsigned char * indata,unsigned char * outdata)70 void 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
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 ( ( ((unsigned long)indata & (sizeof(RC4_CHUNK)-1)) |
124 ((unsigned long)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&~(sizeof(RC4_CHUNK)-1);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&~(sizeof(RC4_CHUNK)-1);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=(int)(len>>3L);
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=(int)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