2 Unix SMB/CIFS implementation.
4 a partial implementation of RC4 designed for use in the
5 SMB authentication protocol
7 Copyright (C) Andrew Tridgell 1998
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
30 /* Perform RC4 on a block of data using specified key. "data" is a pointer
31 to the block to be processed. Output is written to same memory as input,
32 so caller may need to make a copy before calling this function, since
33 the input will be overwritten.
35 Taken from Samba source code. Modified to allow us to maintain state
36 between calls to crypt_rc4.
39 void crypt_rc4_init(rc4_state_struct *rc4_state,
40 const unsigned char *key, int key_len)
46 memset(rc4_state, 0, sizeof(rc4_state_struct));
47 s_box = rc4_state->s_box;
49 for (ind = 0; ind < 256; ind++)
51 s_box[ind] = (unsigned char)ind;
54 for( ind = 0; ind < 256; ind++)
58 j += (s_box[ind] + key[ind%key_len]);
61 s_box[ind] = s_box[j];
67 void crypt_rc4(rc4_state_struct *rc4_state, unsigned char *data, int data_len)
70 unsigned char index_i;
71 unsigned char index_j;
74 /* retrieve current state from the state struct (so we can resume where
76 index_i = rc4_state->index_i;
77 index_j = rc4_state->index_j;
78 s_box = rc4_state->s_box;
80 for( ind = 0; ind < data_len; ind++)
86 index_j += s_box[index_i];
89 s_box[index_i] = s_box[index_j];
92 t = s_box[index_i] + s_box[index_j];
93 data[ind] = data[ind] ^ s_box[t];
96 /* Store the updated state */
97 rc4_state->index_i = index_i;
98 rc4_state->index_j = index_j;
102 * Editor modelines - http://www.wireshark.org/tools/modelines.html
107 * indent-tabs-mode: nil
110 * ex: set shiftwidth=2 tabstop=8 expandtab:
111 * :indentSize=2:tabSize=8:noTabs=true: