rc4_skey.c revision 296465 
1/* crypto/rc4/rc4_skey.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#include <openssl/opensslv.h>
62#include <openssl/crypto.h>
63#ifdef OPENSSL_FIPS
64# include <openssl/fips.h>
65#endif
66
67const char RC4_version[] = "RC4" OPENSSL_VERSION_PTEXT;
68
69const char *RC4_options(void)
70{
71#ifdef RC4_INDEX
72    if (sizeof(RC4_INT) == 1)
73        return ("rc4(idx,char)");
74    else
75        return ("rc4(idx,int)");
76#else
77    if (sizeof(RC4_INT) == 1)
78        return ("rc4(ptr,char)");
79    else
80        return ("rc4(ptr,int)");
81#endif
82}
83
84/*-
85 * RC4 as implemented from a posting from
86 * Newsgroups: sci.crypt
87 * From: sterndark@netcom.com (David Sterndark)
88 * Subject: RC4 Algorithm revealed.
89 * Message-ID: <sternCvKL4B.Hyy@netcom.com>
90 * Date: Wed, 14 Sep 1994 06:35:31 GMT
91 */
92
93#ifdef OPENSSL_FIPS
94void private_RC4_set_key(RC4_KEY *key, int len, const unsigned char *data)
95#else
96void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data)
97#endif
98{
99    register RC4_INT tmp;
100    register int id1, id2;
101    register RC4_INT *d;
102    unsigned int i;
103
104    d = &(key->data[0]);
105    key->x = 0;
106    key->y = 0;
107    id1 = id2 = 0;
108
109#define SK_LOOP(d,n) { \
110                tmp=d[(n)]; \
111                id2 = (data[id1] + tmp + id2) & 0xff; \
112                if (++id1 == len) id1=0; \
113                d[(n)]=d[id2]; \
114                d[id2]=tmp; }
115
116#if defined(OPENSSL_CPUID_OBJ) && !defined(OPENSSL_NO_ASM)
117# if    defined(__i386)   || defined(__i386__)   || defined(_M_IX86) || \
118        defined(__INTEL__) || \
119        defined(__x86_64) || defined(__x86_64__) || defined(_M_AMD64)
120    if (sizeof(RC4_INT) > 1) {
121        /*
122         * Unlike all other x86 [and x86_64] implementations,
123         * Intel P4 core [including EM64T] was found to perform
124         * poorly with wider RC4_INT. Performance improvement
125         * for IA-32 hand-coded assembler turned out to be 2.8x
126         * if re-coded for RC4_CHAR! It's however inappropriate
127         * to just switch to RC4_CHAR for x86[_64], as non-P4
128         * implementations suffer from significant performance
129         * losses then, e.g. PIII exhibits >2x deterioration,
130         * and so does Opteron. In order to assure optimal
131         * all-round performance, we detect P4 at run-time by
132         * checking upon reserved bit 20 in CPU capability
133         * vector and set up compressed key schedule, which is
134         * recognized by correspondingly updated assembler
135         * module... Bit 20 is set up by OPENSSL_ia32_cpuid.
136         *
137         *                              <appro@fy.chalmers.se>
138         */
139#  ifdef OPENSSL_FIPS
140        unsigned long *ia32cap_ptr = OPENSSL_ia32cap_loc();
141        if (ia32cap_ptr && (*ia32cap_ptr & (1 << 20))) {
142#  else
143        if (OPENSSL_ia32cap_P & (1 << 20)) {
144#  endif
145            unsigned char *cp = (unsigned char *)d;
146
147            for (i = 0; i < 256; i++)
148                cp[i] = i;
149            for (i = 0; i < 256; i++)
150                SK_LOOP(cp, i);
151            /* mark schedule as compressed! */
152            d[256 / sizeof(RC4_INT)] = -1;
153            return;
154        }
155    }
156# endif
157#endif
158    for (i = 0; i < 256; i++)
159        d[i] = i;
160    for (i = 0; i < 256; i += 4) {
161        SK_LOOP(d, i + 0);
162        SK_LOOP(d, i + 1);
163        SK_LOOP(d, i + 2);
164        SK_LOOP(d, i + 3);
165    }
166}
167