Proper support for OpenBSD-i386 shared build, including assember modules!
[openssl.git] / crypto / rc4 / rc4_enc.c
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, 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);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);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         }