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Diffstat (limited to 'polarssl/src/library/arc4.c')
| -rw-r--r-- | polarssl/src/library/arc4.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/polarssl/src/library/arc4.c b/polarssl/src/library/arc4.c new file mode 100644 index 0000000..07665ad --- /dev/null +++ b/polarssl/src/library/arc4.c @@ -0,0 +1,169 @@ +/* + * An implementation of the ARCFOUR algorithm + * + * Copyright (C) 2006-2010, Brainspark B.V. + * + * This file is part of PolarSSL (http://www.polarssl.org) + * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org> + * + * All rights reserved. + * + * 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., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ +/* + * 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, const unsigned char *key, unsigned int keylen ) +{ + int i, j, a; + unsigned int k; + 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 + */ +int arc4_crypt( arc4_context *ctx, size_t length, const unsigned char *input, + unsigned char *output ) +{ + int x, y, a, b; + size_t i; + unsigned char *m; + + x = ctx->x; + y = ctx->y; + m = ctx->m; + + for( i = 0; i < length; 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; + + output[i] = (unsigned char) + ( input[i] ^ m[(unsigned char)( a + b )] ); + } + + ctx->x = x; + ctx->y = y; + + return( 0 ); +} + +#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 ibuf[8]; + unsigned char obuf[8]; + arc4_context ctx; + + for( i = 0; i < 3; i++ ) + { + if( verbose != 0 ) + printf( " ARC4 test #%d: ", i + 1 ); + + memcpy( ibuf, arc4_test_pt[i], 8 ); + + arc4_setup( &ctx, (unsigned char *) arc4_test_key[i], 8 ); + arc4_crypt( &ctx, 8, ibuf, obuf ); + + if( memcmp( obuf, 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 |