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92b96797 FB |
1 | /* |
2 | * Copyright (c) 1996, 2003 VIA Networking Technologies, Inc. | |
3 | * All rights reserved. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along | |
16 | * with this program; if not, write to the Free Software Foundation, Inc., | |
17 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 | * | |
19 | * File: rc4.c | |
20 | * | |
21 | * Purpose: | |
22 | * | |
23 | * Functions: | |
24 | * | |
25 | * Revision History: | |
26 | * | |
27 | * Author: Kyle Hsu | |
28 | * | |
29 | * Date: Sep 4, 2002 | |
30 | * | |
31 | */ | |
32 | ||
92b96797 | 33 | #include "rc4.h" |
92b96797 | 34 | |
cc856e61 | 35 | void rc4_init(PRC4Ext pRC4, PBYTE pbyKey, unsigned int cbKey_len) |
92b96797 | 36 | { |
cc856e61 AM |
37 | unsigned int ust1, ust2; |
38 | unsigned int keyindex; | |
39 | unsigned int stateindex; | |
69d5b491 | 40 | PBYTE pbyst; |
cc856e61 | 41 | unsigned int idx; |
92b96797 | 42 | |
69d5b491 DKT |
43 | pbyst = pRC4->abystate; |
44 | pRC4->ux = 0; | |
45 | pRC4->uy = 0; | |
46 | for (idx = 0; idx < 256; idx++) | |
47 | pbyst[idx] = (BYTE)idx; | |
48 | keyindex = 0; | |
49 | stateindex = 0; | |
50 | for (idx = 0; idx < 256; idx++) { | |
51 | ust1 = pbyst[idx]; | |
52 | stateindex = (stateindex + pbyKey[keyindex] + ust1) & 0xff; | |
53 | ust2 = pbyst[stateindex]; | |
54 | pbyst[stateindex] = (BYTE)ust1; | |
55 | pbyst[idx] = (BYTE)ust2; | |
56 | if (++keyindex >= cbKey_len) | |
57 | keyindex = 0; | |
58 | } | |
92b96797 FB |
59 | } |
60 | ||
cc856e61 | 61 | unsigned int rc4_byte(PRC4Ext pRC4) |
92b96797 | 62 | { |
cc856e61 AM |
63 | unsigned int ux; |
64 | unsigned int uy; | |
65 | unsigned int ustx, usty; | |
69d5b491 | 66 | PBYTE pbyst; |
92b96797 | 67 | |
69d5b491 DKT |
68 | pbyst = pRC4->abystate; |
69 | ux = (pRC4->ux + 1) & 0xff; | |
70 | ustx = pbyst[ux]; | |
71 | uy = (ustx + pRC4->uy) & 0xff; | |
72 | usty = pbyst[uy]; | |
73 | pRC4->ux = ux; | |
74 | pRC4->uy = uy; | |
75 | pbyst[uy] = (BYTE)ustx; | |
76 | pbyst[ux] = (BYTE)usty; | |
92b96797 | 77 | |
69d5b491 | 78 | return pbyst[(ustx + usty) & 0xff]; |
92b96797 FB |
79 | } |
80 | ||
8611a29a | 81 | void rc4_encrypt(PRC4Ext pRC4, PBYTE pbyDest, |
cc856e61 | 82 | PBYTE pbySrc, unsigned int cbData_len) |
92b96797 | 83 | { |
cc856e61 | 84 | unsigned int ii; |
69d5b491 DKT |
85 | for (ii = 0; ii < cbData_len; ii++) |
86 | pbyDest[ii] = (BYTE)(pbySrc[ii] ^ rc4_byte(pRC4)); | |
92b96797 | 87 | } |