/src/samba/third_party/heimdal/lib/hcrypto/rc4.c
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1 | | /* |
2 | | * Copyright (c) 2004 Kungliga Tekniska Högskolan |
3 | | * (Royal Institute of Technology, Stockholm, Sweden). |
4 | | * All rights reserved. |
5 | | * |
6 | | * Redistribution and use in source and binary forms, with or without |
7 | | * modification, are permitted provided that the following conditions |
8 | | * are met: |
9 | | * |
10 | | * 1. Redistributions of source code must retain the above copyright |
11 | | * notice, this list of conditions and the following disclaimer. |
12 | | * |
13 | | * 2. Redistributions in binary form must reproduce the above copyright |
14 | | * notice, this list of conditions and the following disclaimer in the |
15 | | * documentation and/or other materials provided with the distribution. |
16 | | * |
17 | | * 3. Neither the name of the Institute nor the names of its contributors |
18 | | * may be used to endorse or promote products derived from this software |
19 | | * without specific prior written permission. |
20 | | * |
21 | | * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND |
22 | | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
23 | | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
24 | | * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE |
25 | | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
26 | | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
27 | | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
28 | | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
29 | | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
30 | | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
31 | | * SUCH DAMAGE. |
32 | | */ |
33 | | |
34 | | /* implemented from description in draft-kaukonen-cipher-arcfour-03.txt */ |
35 | | |
36 | | #include <config.h> |
37 | | #include <roken.h> |
38 | | |
39 | | #include <rc4.h> |
40 | | |
41 | 0 | #define SWAP(k,x,y) \ |
42 | 0 | { unsigned int _t; \ |
43 | 0 | _t = k->state[x]; \ |
44 | 0 | k->state[x] = k->state[y]; \ |
45 | 0 | k->state[y] = _t; \ |
46 | 0 | } |
47 | | |
48 | | void |
49 | | RC4_set_key(RC4_KEY *key, const int len, const unsigned char *data) |
50 | 0 | { |
51 | 0 | int i, j; |
52 | |
|
53 | 0 | for (i = 0; i < 256; i++) |
54 | 0 | key->state[i] = i; |
55 | 0 | for (i = 0, j = 0; i < 256; i++) { |
56 | 0 | j = (j + key->state[i] + data[i % len]) % 256; |
57 | 0 | SWAP(key, i, j); |
58 | 0 | } |
59 | 0 | key->x = key->y = 0; |
60 | 0 | } |
61 | | |
62 | | void |
63 | | RC4(RC4_KEY *key, const int len, const unsigned char *in, unsigned char *out) |
64 | 0 | { |
65 | 0 | int i, t; |
66 | 0 | unsigned x, y; |
67 | |
|
68 | 0 | x = key->x; |
69 | 0 | y = key->y; |
70 | 0 | for (i = 0; i < len; i++) { |
71 | 0 | x = (x + 1) % 256; |
72 | 0 | y = (y + key->state[x]) % 256; |
73 | 0 | SWAP(key, x, y); |
74 | 0 | t = (key->state[x] + key->state[y]) % 256; |
75 | 0 | *out++ = key->state[t] ^ *in++; |
76 | 0 | } |
77 | 0 | key->x = x; |
78 | 0 | key->y = y; |
79 | 0 | } |