Mercurial > pidgin3 / file diff

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libpurple/protocols/myspace/crypt-rc4.c	Sat Apr 21 03:15:48 2007 +0000
@@ -0,0 +1,103 @@
+/* 
+   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 12116 2004-09-27 23:29:22Z guy $
+   
+   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.
+
+   
+   Modified by Jeff Connelly for MySpaceIM Gaim plugin.
+*/
+
+#include <glib.h>
+#include <string.h>
+
+#include "crypt-rc4.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.  
+   
+   Taken from Samba source code.  Modified to allow us to maintain state
+   between calls to crypt_rc4.
+*/
+
+void crypt_rc4_init(rc4_state_struct *rc4_state, 
+		    const unsigned char *key, int key_len)
+{
+  int ind;
+  unsigned char j = 0;
+  unsigned char *s_box;
+
+  memset(rc4_state, 0, sizeof(rc4_state_struct));
+  s_box = rc4_state->s_box;
+  
+  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%key_len]);
+
+     tc = s_box[ind];
+     s_box[ind] = s_box[j];
+     s_box[j] = tc;
+  }
+
+}
+
+void crypt_rc4(rc4_state_struct *rc4_state, unsigned char *data, int data_len)
+{
+  unsigned char *s_box;
+  unsigned char index_i;
+  unsigned char index_j;
+  int ind;
+
+  /* retrieve current state from the state struct (so we can resume where
+     we left off) */
+  index_i = rc4_state->index_i;
+  index_j = rc4_state->index_j;
+  s_box = rc4_state->s_box;
+
+  for( ind = 0; ind < data_len; 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];
+  }
+
+  /* Store the updated state */
+  rc4_state->index_i = index_i;
+  rc4_state->index_j = index_j;
+}