blob: 40656edec396ac94e2b330f91dcad55af77f8d4b [file] [log] [blame]
/*
* An implementation of the ARCFOUR algorithm
*
* Based on XySSL: Copyright (C) 2006-2008 Christophe Devine
*
* Copyright (C) 2009 Paul Bakker <polarssl_maintainer at polarssl dot org>
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the names of PolarSSL or XySSL nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* The ARCFOUR algorithm was publicly disclosed on 94/09.
*
* http://groups.google.com/group/sci.crypt/msg/10a300c9d21afca0
*/
#include "polarssl/config.h"
#if defined(POLARSSL_ARC4_C)
#include "polarssl/arc4.h"
/*
* ARC4 key schedule
*/
void arc4_setup( arc4_context *ctx, unsigned char *key, int keylen )
{
int i, j, k, a;
unsigned char *m;
ctx->x = 0;
ctx->y = 0;
m = ctx->m;
for( i = 0; i < 256; i++ )
m[i] = (unsigned char) i;
j = k = 0;
for( i = 0; i < 256; i++, k++ )
{
if( k >= keylen ) k = 0;
a = m[i];
j = ( j + a + key[k] ) & 0xFF;
m[i] = m[j];
m[j] = (unsigned char) a;
}
}
/*
* ARC4 cipher function
*/
void arc4_crypt( arc4_context *ctx, unsigned char *buf, int buflen )
{
int i, x, y, a, b;
unsigned char *m;
x = ctx->x;
y = ctx->y;
m = ctx->m;
for( i = 0; i < buflen; i++ )
{
x = ( x + 1 ) & 0xFF; a = m[x];
y = ( y + a ) & 0xFF; b = m[y];
m[x] = (unsigned char) b;
m[y] = (unsigned char) a;
buf[i] = (unsigned char)
( buf[i] ^ m[(unsigned char)( a + b )] );
}
ctx->x = x;
ctx->y = y;
}
#if defined(POLARSSL_SELF_TEST)
#include <string.h>
#include <stdio.h>
/*
* ARC4 tests vectors as posted by Eric Rescorla in sep. 1994:
*
* http://groups.google.com/group/comp.security.misc/msg/10a300c9d21afca0
*/
static const unsigned char arc4_test_key[3][8] =
{
{ 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF },
{ 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF },
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
};
static const unsigned char arc4_test_pt[3][8] =
{
{ 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF },
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
};
static const unsigned char arc4_test_ct[3][8] =
{
{ 0x75, 0xB7, 0x87, 0x80, 0x99, 0xE0, 0xC5, 0x96 },
{ 0x74, 0x94, 0xC2, 0xE7, 0x10, 0x4B, 0x08, 0x79 },
{ 0xDE, 0x18, 0x89, 0x41, 0xA3, 0x37, 0x5D, 0x3A }
};
/*
* Checkup routine
*/
int arc4_self_test( int verbose )
{
int i;
unsigned char buf[8];
arc4_context ctx;
for( i = 0; i < 3; i++ )
{
if( verbose != 0 )
printf( " ARC4 test #%d: ", i + 1 );
memcpy( buf, arc4_test_pt[i], 8 );
arc4_setup( &ctx, (unsigned char *) arc4_test_key[i], 8 );
arc4_crypt( &ctx, buf, 8 );
if( memcmp( buf, arc4_test_ct[i], 8 ) != 0 )
{
if( verbose != 0 )
printf( "failed\n" );
return( 1 );
}
if( verbose != 0 )
printf( "passed\n" );
}
if( verbose != 0 )
printf( "\n" );
return( 0 );
}
#endif
#endif