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
63const char RC4_version[]="RC4" OPENSSL_VERSION_PTEXT;
64
65const char *RC4_options(void)
66	{
67#ifdef RC4_INDEX
68	if (sizeof(RC4_INT) == 1)
69		return("rc4(idx,char)");
70	else
71		return("rc4(idx,int)");
72#else
73	if (sizeof(RC4_INT) == 1)
74		return("rc4(ptr,char)");
75	else
76		return("rc4(ptr,int)");
77#endif
78	}
79
80/* RC4 as implemented from a posting from
81 * Newsgroups: sci.crypt
82 * From: sterndark@netcom.com (David Sterndark)
83 * Subject: RC4 Algorithm revealed.
84 * Message-ID: <sternCvKL4B.Hyy@netcom.com>
85 * Date: Wed, 14 Sep 1994 06:35:31 GMT
86 */
87
88void private_RC4_set_key(RC4_KEY *key, int len, const unsigned char *data)
89	{
90        register RC4_INT tmp;
91        register int id1,id2;
92        register RC4_INT *d;
93        unsigned int i;
94
95        d= &(key->data[0]);
96        key->x = 0;
97        key->y = 0;
98        id1=id2=0;
99
100#define SK_LOOP(d,n) { \
101		tmp=d[(n)]; \
102		id2 = (data[id1] + tmp + id2) & 0xff; \
103		if (++id1 == len) id1=0; \
104		d[(n)]=d[id2]; \
105		d[id2]=tmp; }
106
107	for (i=0; i < 256; i++) d[i]=i;
108	for (i=0; i < 256; i+=4)
109		{
110		SK_LOOP(d,i+0);
111		SK_LOOP(d,i+1);
112		SK_LOOP(d,i+2);
113		SK_LOOP(d,i+3);
114		}
115	}
116
117