/* * An implementation of the ARCFOUR algorithm * * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later * * This file is provided under the Apache License 2.0, or the * GNU General Public License v2.0 or later. * * ********** * Apache License 2.0: * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * ********** * * ********** * GNU General Public License v2.0 or later: * * 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 */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_ARC4_C) #include "mbedtls/arc4.h" #include "mbedtls/platform_util.h" #include <string.h> #if defined(MBEDTLS_SELF_TEST) #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #include <stdio.h> #define mbedtls_printf printf #endif /* MBEDTLS_PLATFORM_C */ #endif /* MBEDTLS_SELF_TEST */ #if !defined(MBEDTLS_ARC4_ALT) void mbedtls_arc4_init( mbedtls_arc4_context *ctx ) { memset( ctx, 0, sizeof( mbedtls_arc4_context ) ); } void mbedtls_arc4_free( mbedtls_arc4_context *ctx ) { if( ctx == NULL ) return; mbedtls_platform_zeroize( ctx, sizeof( mbedtls_arc4_context ) ); } /* * ARC4 key schedule */ void mbedtls_arc4_setup( mbedtls_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 mbedtls_arc4_crypt( mbedtls_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 ); } #endif /* !MBEDTLS_ARC4_ALT */ #if defined(MBEDTLS_SELF_TEST) /* * 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 mbedtls_arc4_self_test( int verbose ) { int i, ret = 0; unsigned char ibuf[8]; unsigned char obuf[8]; mbedtls_arc4_context ctx; mbedtls_arc4_init( &ctx ); for( i = 0; i < 3; i++ ) { if( verbose != 0 ) mbedtls_printf( " ARC4 test #%d: ", i + 1 ); memcpy( ibuf, arc4_test_pt[i], 8 ); mbedtls_arc4_setup( &ctx, arc4_test_key[i], 8 ); mbedtls_arc4_crypt( &ctx, 8, ibuf, obuf ); if( memcmp( obuf, arc4_test_ct[i], 8 ) != 0 ) { if( verbose != 0 ) mbedtls_printf( "failed\n" ); ret = 1; goto exit; } if( verbose != 0 ) mbedtls_printf( "passed\n" ); } if( verbose != 0 ) mbedtls_printf( "\n" ); exit: mbedtls_arc4_free( &ctx ); return( ret ); } #endif /* MBEDTLS_SELF_TEST */ #endif /* MBEDTLS_ARC4_C */