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+/*! \file rc4.c
+    \brief Source file for RC4 stream cipher routines
+         \author Damien Miller <djm@mindrot.org>
+         \version 0.0.0
+         \date 1999
+         
+         A simple implementation of the RC4 stream cipher, based on the
+         description given in _Bruce Schneier's_ "Applied Cryptography"
+         2nd edition.
+
+         Copyright 1999 Damien Miller
+
+         Permission is hereby granted, free of charge, to any person
+         obtaining a copy of this software and associated documentation
+         files (the "Software"), to deal in the Software without
+         restriction, including without limitation the rights to use, copy,
+         modify, merge, publish, distribute, sublicense, and/or sell copies
+         of the Software, and to permit persons to whom the Software is
+         furnished to do so, subject to the following conditions:
+
+         The above copyright notice and this permission notice shall be
+         included in all copies or substantial portions of the Software.
+
+         THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+         KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+         WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
+         AND NONINFRINGEMENT.  IN NO EVENT SHALL DAMIEN MILLER BE LIABLE
+         FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+         CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+         WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+         \warning None of these functions clears its memory after use. It
+         \warning is the responsability of the calling routines to ensure
+         \warning that any sensitive data (keystream, key or plaintext) is
+         \warning properly erased after use.
+         
+         \warning The name "RC4" is trademarked in the United States, 
+         \warning you may need to use "RC4 compatible" or "ARC4" 
+         \warning (Alleged RC4).
+*/
+
+/* $Id: rc4.c,v 1.1.1.1 1999/10/26 05:48:13 damien Exp $ */
+
+#include "rc4.h"
+
+
+void rc4_key(rc4_t *r, unsigned char *key, int len)
+{
+        int t;
+        
+        for(r->i = 0; r->i < 256; r->i++)
+                r->s[r->i] = r->i;
+
+        r->j = 0;
+        for(r->i = 0; r->i < 256; r->i++)
+        {
+                r->j = (r->j + r->s[r->i] + key[r->i % len]) % 256;
+                t = r->s[r->i];
+                r->s[r->i] = r->s[r->j];
+                r->s[r->j] = t;
+        }
+        r->i = r->j = 0;
+}
+
+void rc4_crypt(rc4_t *r, unsigned char *plaintext, int len)
+{
+        int t;
+        int c;
+
+        c = 0;  
+        while(c < len)
+        {
+                r->i = (r->i + 1) % 256;
+                r->j = (r->j + r->s[r->i]) % 256;
+                t = r->s[r->i];
+                r->s[r->i] = r->s[r->j];
+                r->s[r->j] = t;
+
+                t = (r->s[r->i] + r->s[r->j]) % 256;
+
+                plaintext[c] ^= r->s[t];
+                c++;
+        }
+}
+
+void rc4_getbytes(rc4_t *r, unsigned char *buffer, int len)
+{
+        int t;
+        int c;
+
+        c = 0;  
+        while(c < len)
+        {
+                r->i = (r->i + 1) % 256;
+                r->j = (r->j + r->s[r->i]) % 256;
+                t = r->s[r->i];
+                r->s[r->i] = r->s[r->j];
+                r->s[r->j] = t;
+
+                t = (r->s[r->i] + r->s[r->j]) % 256;
+                
+                buffer[c] = r->s[t];
+                c++;
+        }
+}