Mark Radbourne / mbedtls

mbed TLS Build

Dependents:   Encrypt_Decrypt1 mbed_blink_tls encrypt encrypt

library/arc4.c@0:cdf462088d13, 2017-01-05 (annotated)

Committer:
markrad
Date:
Thu Jan 05 00:18:44 2017 +0000
Revision:
0:cdf462088d13
Initial commit

Who changed what in which revision?

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markrad 0:cdf462088d13 1 /*
markrad 0:cdf462088d13 2 * An implementation of the ARCFOUR algorithm
markrad 0:cdf462088d13 3 *
markrad 0:cdf462088d13 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
markrad 0:cdf462088d13 5 * SPDX-License-Identifier: Apache-2.0
markrad 0:cdf462088d13 6 *
markrad 0:cdf462088d13 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
markrad 0:cdf462088d13 8 * not use this file except in compliance with the License.
markrad 0:cdf462088d13 9 * You may obtain a copy of the License at
markrad 0:cdf462088d13 10 *
markrad 0:cdf462088d13 11 * http://www.apache.org/licenses/LICENSE-2.0
markrad 0:cdf462088d13 12 *
markrad 0:cdf462088d13 13 * Unless required by applicable law or agreed to in writing, software
markrad 0:cdf462088d13 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
markrad 0:cdf462088d13 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
markrad 0:cdf462088d13 16 * See the License for the specific language governing permissions and
markrad 0:cdf462088d13 17 * limitations under the License.
markrad 0:cdf462088d13 18 *
markrad 0:cdf462088d13 19 * This file is part of mbed TLS (https://tls.mbed.org)
markrad 0:cdf462088d13 20 */
markrad 0:cdf462088d13 21 /*
markrad 0:cdf462088d13 22 * The ARCFOUR algorithm was publicly disclosed on 94/09.
markrad 0:cdf462088d13 23 *
markrad 0:cdf462088d13 24 * http://groups.google.com/group/sci.crypt/msg/10a300c9d21afca0
markrad 0:cdf462088d13 25 */
markrad 0:cdf462088d13 26
markrad 0:cdf462088d13 27 #if !defined(MBEDTLS_CONFIG_FILE)
markrad 0:cdf462088d13 28 #include "mbedtls/config.h"
markrad 0:cdf462088d13 29 #else
markrad 0:cdf462088d13 30 #include MBEDTLS_CONFIG_FILE
markrad 0:cdf462088d13 31 #endif
markrad 0:cdf462088d13 32
markrad 0:cdf462088d13 33 #if defined(MBEDTLS_ARC4_C)
markrad 0:cdf462088d13 34
markrad 0:cdf462088d13 35 #include "mbedtls/arc4.h"
markrad 0:cdf462088d13 36
markrad 0:cdf462088d13 37 #include <string.h>
markrad 0:cdf462088d13 38
markrad 0:cdf462088d13 39 #if defined(MBEDTLS_SELF_TEST)
markrad 0:cdf462088d13 40 #if defined(MBEDTLS_PLATFORM_C)
markrad 0:cdf462088d13 41 #include "mbedtls/platform.h"
markrad 0:cdf462088d13 42 #else
markrad 0:cdf462088d13 43 #include <stdio.h>
markrad 0:cdf462088d13 44 #define mbedtls_printf printf
markrad 0:cdf462088d13 45 #endif /* MBEDTLS_PLATFORM_C */
markrad 0:cdf462088d13 46 #endif /* MBEDTLS_SELF_TEST */
markrad 0:cdf462088d13 47
markrad 0:cdf462088d13 48 #if !defined(MBEDTLS_ARC4_ALT)
markrad 0:cdf462088d13 49
markrad 0:cdf462088d13 50 /* Implementation that should never be optimized out by the compiler */
markrad 0:cdf462088d13 51 static void mbedtls_zeroize( void *v, size_t n ) {
markrad 0:cdf462088d13 52 volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
markrad 0:cdf462088d13 53 }
markrad 0:cdf462088d13 54
markrad 0:cdf462088d13 55 void mbedtls_arc4_init( mbedtls_arc4_context *ctx )
markrad 0:cdf462088d13 56 {
markrad 0:cdf462088d13 57 memset( ctx, 0, sizeof( mbedtls_arc4_context ) );
markrad 0:cdf462088d13 58 }
markrad 0:cdf462088d13 59
markrad 0:cdf462088d13 60 void mbedtls_arc4_free( mbedtls_arc4_context *ctx )
markrad 0:cdf462088d13 61 {
markrad 0:cdf462088d13 62 if( ctx == NULL )
markrad 0:cdf462088d13 63 return;
markrad 0:cdf462088d13 64
markrad 0:cdf462088d13 65 mbedtls_zeroize( ctx, sizeof( mbedtls_arc4_context ) );
markrad 0:cdf462088d13 66 }
markrad 0:cdf462088d13 67
markrad 0:cdf462088d13 68 /*
markrad 0:cdf462088d13 69 * ARC4 key schedule
markrad 0:cdf462088d13 70 */
markrad 0:cdf462088d13 71 void mbedtls_arc4_setup( mbedtls_arc4_context *ctx, const unsigned char *key,
markrad 0:cdf462088d13 72 unsigned int keylen )
markrad 0:cdf462088d13 73 {
markrad 0:cdf462088d13 74 int i, j, a;
markrad 0:cdf462088d13 75 unsigned int k;
markrad 0:cdf462088d13 76 unsigned char *m;
markrad 0:cdf462088d13 77
markrad 0:cdf462088d13 78 ctx->x = 0;
markrad 0:cdf462088d13 79 ctx->y = 0;
markrad 0:cdf462088d13 80 m = ctx->m;
markrad 0:cdf462088d13 81
markrad 0:cdf462088d13 82 for( i = 0; i < 256; i++ )
markrad 0:cdf462088d13 83 m[i] = (unsigned char) i;
markrad 0:cdf462088d13 84
markrad 0:cdf462088d13 85 j = k = 0;
markrad 0:cdf462088d13 86
markrad 0:cdf462088d13 87 for( i = 0; i < 256; i++, k++ )
markrad 0:cdf462088d13 88 {
markrad 0:cdf462088d13 89 if( k >= keylen ) k = 0;
markrad 0:cdf462088d13 90
markrad 0:cdf462088d13 91 a = m[i];
markrad 0:cdf462088d13 92 j = ( j + a + key[k] ) & 0xFF;
markrad 0:cdf462088d13 93 m[i] = m[j];
markrad 0:cdf462088d13 94 m[j] = (unsigned char) a;
markrad 0:cdf462088d13 95 }
markrad 0:cdf462088d13 96 }
markrad 0:cdf462088d13 97
markrad 0:cdf462088d13 98 /*
markrad 0:cdf462088d13 99 * ARC4 cipher function
markrad 0:cdf462088d13 100 */
markrad 0:cdf462088d13 101 int mbedtls_arc4_crypt( mbedtls_arc4_context *ctx, size_t length, const unsigned char *input,
markrad 0:cdf462088d13 102 unsigned char *output )
markrad 0:cdf462088d13 103 {
markrad 0:cdf462088d13 104 int x, y, a, b;
markrad 0:cdf462088d13 105 size_t i;
markrad 0:cdf462088d13 106 unsigned char *m;
markrad 0:cdf462088d13 107
markrad 0:cdf462088d13 108 x = ctx->x;
markrad 0:cdf462088d13 109 y = ctx->y;
markrad 0:cdf462088d13 110 m = ctx->m;
markrad 0:cdf462088d13 111
markrad 0:cdf462088d13 112 for( i = 0; i < length; i++ )
markrad 0:cdf462088d13 113 {
markrad 0:cdf462088d13 114 x = ( x + 1 ) & 0xFF; a = m[x];
markrad 0:cdf462088d13 115 y = ( y + a ) & 0xFF; b = m[y];
markrad 0:cdf462088d13 116
markrad 0:cdf462088d13 117 m[x] = (unsigned char) b;
markrad 0:cdf462088d13 118 m[y] = (unsigned char) a;
markrad 0:cdf462088d13 119
markrad 0:cdf462088d13 120 output[i] = (unsigned char)
markrad 0:cdf462088d13 121 ( input[i] ^ m[(unsigned char)( a + b )] );
markrad 0:cdf462088d13 122 }
markrad 0:cdf462088d13 123
markrad 0:cdf462088d13 124 ctx->x = x;
markrad 0:cdf462088d13 125 ctx->y = y;
markrad 0:cdf462088d13 126
markrad 0:cdf462088d13 127 return( 0 );
markrad 0:cdf462088d13 128 }
markrad 0:cdf462088d13 129
markrad 0:cdf462088d13 130 #endif /* !MBEDTLS_ARC4_ALT */
markrad 0:cdf462088d13 131
markrad 0:cdf462088d13 132 #if defined(MBEDTLS_SELF_TEST)
markrad 0:cdf462088d13 133 /*
markrad 0:cdf462088d13 134 * ARC4 tests vectors as posted by Eric Rescorla in sep. 1994:
markrad 0:cdf462088d13 135 *
markrad 0:cdf462088d13 136 * http://groups.google.com/group/comp.security.misc/msg/10a300c9d21afca0
markrad 0:cdf462088d13 137 */
markrad 0:cdf462088d13 138 static const unsigned char arc4_test_key[3][8] =
markrad 0:cdf462088d13 139 {
markrad 0:cdf462088d13 140 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF },
markrad 0:cdf462088d13 141 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF },
markrad 0:cdf462088d13 142 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
markrad 0:cdf462088d13 143 };
markrad 0:cdf462088d13 144
markrad 0:cdf462088d13 145 static const unsigned char arc4_test_pt[3][8] =
markrad 0:cdf462088d13 146 {
markrad 0:cdf462088d13 147 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF },
markrad 0:cdf462088d13 148 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
markrad 0:cdf462088d13 149 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
markrad 0:cdf462088d13 150 };
markrad 0:cdf462088d13 151
markrad 0:cdf462088d13 152 static const unsigned char arc4_test_ct[3][8] =
markrad 0:cdf462088d13 153 {
markrad 0:cdf462088d13 154 { 0x75, 0xB7, 0x87, 0x80, 0x99, 0xE0, 0xC5, 0x96 },
markrad 0:cdf462088d13 155 { 0x74, 0x94, 0xC2, 0xE7, 0x10, 0x4B, 0x08, 0x79 },
markrad 0:cdf462088d13 156 { 0xDE, 0x18, 0x89, 0x41, 0xA3, 0x37, 0x5D, 0x3A }
markrad 0:cdf462088d13 157 };
markrad 0:cdf462088d13 158
markrad 0:cdf462088d13 159 /*
markrad 0:cdf462088d13 160 * Checkup routine
markrad 0:cdf462088d13 161 */
markrad 0:cdf462088d13 162 int mbedtls_arc4_self_test( int verbose )
markrad 0:cdf462088d13 163 {
markrad 0:cdf462088d13 164 int i, ret = 0;
markrad 0:cdf462088d13 165 unsigned char ibuf[8];
markrad 0:cdf462088d13 166 unsigned char obuf[8];
markrad 0:cdf462088d13 167 mbedtls_arc4_context ctx;
markrad 0:cdf462088d13 168
markrad 0:cdf462088d13 169 mbedtls_arc4_init( &ctx );
markrad 0:cdf462088d13 170
markrad 0:cdf462088d13 171 for( i = 0; i < 3; i++ )
markrad 0:cdf462088d13 172 {
markrad 0:cdf462088d13 173 if( verbose != 0 )
markrad 0:cdf462088d13 174 mbedtls_printf( " ARC4 test #%d: ", i + 1 );
markrad 0:cdf462088d13 175
markrad 0:cdf462088d13 176 memcpy( ibuf, arc4_test_pt[i], 8 );
markrad 0:cdf462088d13 177
markrad 0:cdf462088d13 178 mbedtls_arc4_setup( &ctx, arc4_test_key[i], 8 );
markrad 0:cdf462088d13 179 mbedtls_arc4_crypt( &ctx, 8, ibuf, obuf );
markrad 0:cdf462088d13 180
markrad 0:cdf462088d13 181 if( memcmp( obuf, arc4_test_ct[i], 8 ) != 0 )
markrad 0:cdf462088d13 182 {
markrad 0:cdf462088d13 183 if( verbose != 0 )
markrad 0:cdf462088d13 184 mbedtls_printf( "failed\n" );
markrad 0:cdf462088d13 185
markrad 0:cdf462088d13 186 ret = 1;
markrad 0:cdf462088d13 187 goto exit;
markrad 0:cdf462088d13 188 }
markrad 0:cdf462088d13 189
markrad 0:cdf462088d13 190 if( verbose != 0 )
markrad 0:cdf462088d13 191 mbedtls_printf( "passed\n" );
markrad 0:cdf462088d13 192 }
markrad 0:cdf462088d13 193
markrad 0:cdf462088d13 194 if( verbose != 0 )
markrad 0:cdf462088d13 195 mbedtls_printf( "\n" );
markrad 0:cdf462088d13 196
markrad 0:cdf462088d13 197 exit:
markrad 0:cdf462088d13 198 mbedtls_arc4_free( &ctx );
markrad 0:cdf462088d13 199
markrad 0:cdf462088d13 200 return( ret );
markrad 0:cdf462088d13 201 }
markrad 0:cdf462088d13 202
markrad 0:cdf462088d13 203 #endif /* MBEDTLS_SELF_TEST */
markrad 0:cdf462088d13 204
markrad 0:cdf462088d13 205 #endif /* MBEDTLS_ARC4_C */