| Forest Bond | 5449c68 | 2009-04-25 10:30:44 -0400 | [diff] [blame] | 1 | /* |
| 2 | * File: rc4.c |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License along |
| 15 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 16 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 17 | * |
| 18 | * Purpose: |
| 19 | * |
| 20 | * Functions: |
| 21 | * |
| 22 | * Revision History: |
| 23 | * |
| 24 | * Author: Kyle Hsu |
| 25 | * |
| 26 | * Date: Sep 4, 2002 |
| 27 | * |
| 28 | */ |
| 29 | |
| 30 | #if !defined(__RC4_H__) |
| 31 | #include "rc4.h" |
| 32 | #endif |
| 33 | |
| 34 | VOID rc4_init(PRC4Ext pRC4, PBYTE pbyKey, UINT cbKey_len) |
| 35 | { |
| 36 | UINT ust1, ust2; |
| 37 | UINT keyindex; |
| 38 | UINT stateindex; |
| 39 | PBYTE pbyst; |
| 40 | UINT idx; |
| 41 | |
| 42 | pbyst = pRC4->abystate; |
| 43 | pRC4->ux = 0; |
| 44 | pRC4->uy = 0; |
| 45 | for (idx = 0; idx < 256; idx++) |
| 46 | pbyst[idx] = (BYTE)idx; |
| 47 | keyindex = 0; |
| 48 | stateindex = 0; |
| 49 | for (idx = 0; idx < 256; idx++) { |
| 50 | ust1 = pbyst[idx]; |
| 51 | stateindex = (stateindex + pbyKey[keyindex] + ust1) & 0xff; |
| 52 | ust2 = pbyst[stateindex]; |
| 53 | pbyst[stateindex] = (BYTE)ust1; |
| 54 | pbyst[idx] = (BYTE)ust2; |
| 55 | if (++keyindex >= cbKey_len) |
| 56 | keyindex = 0; |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | UINT rc4_byte(PRC4Ext pRC4) |
| 61 | { |
| 62 | UINT ux; |
| 63 | UINT uy; |
| 64 | UINT ustx, usty; |
| 65 | PBYTE pbyst; |
| 66 | |
| 67 | pbyst = pRC4->abystate; |
| 68 | ux = (pRC4->ux + 1) & 0xff; |
| 69 | ustx = pbyst[ux]; |
| 70 | uy = (ustx + pRC4->uy) & 0xff; |
| 71 | usty = pbyst[uy]; |
| 72 | pRC4->ux = ux; |
| 73 | pRC4->uy = uy; |
| 74 | pbyst[uy] = (BYTE)ustx; |
| 75 | pbyst[ux] = (BYTE)usty; |
| 76 | |
| 77 | return pbyst[(ustx + usty) & 0xff]; |
| 78 | } |
| 79 | |
| 80 | VOID rc4_encrypt(PRC4Ext pRC4, PBYTE pbyDest, |
| 81 | PBYTE pbySrc, UINT cbData_len) |
| 82 | { |
| 83 | UINT ii; |
| 84 | for (ii = 0; ii < cbData_len; ii++) |
| 85 | pbyDest[ii] = (BYTE)(pbySrc[ii] ^ rc4_byte(pRC4)); |
| 86 | } |