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Diffstat (limited to 'crypt-rc4.c')
-rw-r--r-- | crypt-rc4.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/crypt-rc4.c b/crypt-rc4.c new file mode 100644 index 0000000000..73d08d45eb --- /dev/null +++ b/crypt-rc4.c @@ -0,0 +1,81 @@ +/* + Unix SMB/CIFS implementation. + + a partial implementation of RC4 designed for use in the + SMB authentication protocol + + Copyright (C) Andrew Tridgell 1998 + + $Id: crypt-rc4.c,v 1.1 2002/12/03 00:37:27 guy Exp $ + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif +#include <glib.h> + +/* Perform RC4 on a block of data using specified key. "data" is a pointer + to the block to be processed. Output is written to same memory as input, + so caller may need to make a copy before calling this function, since + the input will be overwritten. "val" specifies length of data buffer. + "key" is assumed to be a 16 octets in length + + Taken from Samba source code. In the long term, it might be nice to have + the input and output buffer differ, have a length specifier for the key, + and separate the initialization function from the process function (as is + done with the Alleged-RC4 implementation). +*/ + +void crypt_rc4( unsigned char *data, const unsigned char *key, int val) +{ + unsigned char s_box[256]; + unsigned char index_i = 0; + unsigned char index_j = 0; + unsigned char j = 0; + int ind; + + for (ind = 0; ind < 256; ind++) + { + s_box[ind] = (unsigned char)ind; + } + + for( ind = 0; ind < 256; ind++) + { + unsigned char tc; + + j += (s_box[ind] + key[ind%16]); + + tc = s_box[ind]; + s_box[ind] = s_box[j]; + s_box[j] = tc; + } + for( ind = 0; ind < val; ind++) + { + unsigned char tc; + unsigned char t; + + index_i++; + index_j += s_box[index_i]; + + tc = s_box[index_i]; + s_box[index_i] = s_box[index_j]; + s_box[index_j] = tc; + + t = s_box[index_i] + s_box[index_j]; + data[ind] = data[ind] ^ s_box[t]; + } +} |