xtea.c

00001 /*
00002  *  An 32-bit implementation of the XTEA algorithm
00003  *
00004  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
00005  *  SPDX-License-Identifier: Apache-2.0
00006  *
00007  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00008  *  not use this file except in compliance with the License.
00009  *  You may obtain a copy of the License at
00010  *
00011  *  http://www.apache.org/licenses/LICENSE-2.0
00012  *
00013  *  Unless required by applicable law or agreed to in writing, software
00014  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00015  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00016  *  See the License for the specific language governing permissions and
00017  *  limitations under the License.
00018  *
00019  *  This file is part of mbed TLS (https://tls.mbed.org)
00020  */
00021 
00022 #if !defined(MBEDTLS_CONFIG_FILE)
00023 #include "mbedtls/config.h"
00024 #else
00025 #include MBEDTLS_CONFIG_FILE
00026 #endif
00027 
00028 #if defined(MBEDTLS_XTEA_C)
00029 
00030 #include "mbedtls/xtea.h"
00031 #include "mbedtls/platform_util.h"
00032 
00033 #include <string.h>
00034 
00035 #if defined(MBEDTLS_SELF_TEST)
00036 #if defined(MBEDTLS_PLATFORM_C)
00037 #include "mbedtls/platform.h"
00038 #else
00039 #include <stdio.h>
00040 #define mbedtls_printf printf
00041 #endif /* MBEDTLS_PLATFORM_C */
00042 #endif /* MBEDTLS_SELF_TEST */
00043 
00044 #if !defined(MBEDTLS_XTEA_ALT)
00045 
00046 /*
00047  * 32-bit integer manipulation macros (big endian)
00048  */
00049 #ifndef GET_UINT32_BE
00050 #define GET_UINT32_BE(n,b,i)                            \
00051 {                                                       \
00052     (n) = ( (uint32_t) (b)[(i)    ] << 24 )             \
00053         | ( (uint32_t) (b)[(i) + 1] << 16 )             \
00054         | ( (uint32_t) (b)[(i) + 2] <<  8 )             \
00055         | ( (uint32_t) (b)[(i) + 3]       );            \
00056 }
00057 #endif
00058 
00059 #ifndef PUT_UINT32_BE
00060 #define PUT_UINT32_BE(n,b,i)                            \
00061 {                                                       \
00062     (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
00063     (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
00064     (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
00065     (b)[(i) + 3] = (unsigned char) ( (n)       );       \
00066 }
00067 #endif
00068 
00069 void mbedtls_xtea_init( mbedtls_xtea_context *ctx )
00070 {
00071     memset( ctx, 0, sizeof( mbedtls_xtea_context ) );
00072 }
00073 
00074 void mbedtls_xtea_free( mbedtls_xtea_context *ctx )
00075 {
00076     if( ctx == NULL )
00077         return;
00078 
00079     mbedtls_platform_zeroize( ctx, sizeof( mbedtls_xtea_context ) );
00080 }
00081 
00082 /*
00083  * XTEA key schedule
00084  */
00085 void mbedtls_xtea_setup( mbedtls_xtea_context *ctx, const unsigned char key[16] )
00086 {
00087     int i;
00088 
00089     memset( ctx, 0, sizeof(mbedtls_xtea_context) );
00090 
00091     for( i = 0; i < 4; i++ )
00092     {
00093         GET_UINT32_BE( ctx->k [i], key, i << 2 );
00094     }
00095 }
00096 
00097 /*
00098  * XTEA encrypt function
00099  */
00100 int mbedtls_xtea_crypt_ecb( mbedtls_xtea_context *ctx, int mode,
00101                     const unsigned char input[8], unsigned char output[8])
00102 {
00103     uint32_t *k, v0, v1, i;
00104 
00105     k = ctx->k ;
00106 
00107     GET_UINT32_BE( v0, input, 0 );
00108     GET_UINT32_BE( v1, input, 4 );
00109 
00110     if( mode == MBEDTLS_XTEA_ENCRYPT )
00111     {
00112         uint32_t sum = 0, delta = 0x9E3779B9;
00113 
00114         for( i = 0; i < 32; i++ )
00115         {
00116             v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
00117             sum += delta;
00118             v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
00119         }
00120     }
00121     else /* MBEDTLS_XTEA_DECRYPT */
00122     {
00123         uint32_t delta = 0x9E3779B9, sum = delta * 32;
00124 
00125         for( i = 0; i < 32; i++ )
00126         {
00127             v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
00128             sum -= delta;
00129             v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
00130         }
00131     }
00132 
00133     PUT_UINT32_BE( v0, output, 0 );
00134     PUT_UINT32_BE( v1, output, 4 );
00135 
00136     return( 0 );
00137 }
00138 
00139 #if defined(MBEDTLS_CIPHER_MODE_CBC)
00140 /*
00141  * XTEA-CBC buffer encryption/decryption
00142  */
00143 int mbedtls_xtea_crypt_cbc( mbedtls_xtea_context *ctx, int mode, size_t length,
00144                     unsigned char iv[8], const unsigned char *input,
00145                     unsigned char *output)
00146 {
00147     int i;
00148     unsigned char temp[8];
00149 
00150     if( length % 8 )
00151         return( MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH );
00152 
00153     if( mode == MBEDTLS_XTEA_DECRYPT )
00154     {
00155         while( length > 0 )
00156         {
00157             memcpy( temp, input, 8 );
00158             mbedtls_xtea_crypt_ecb( ctx, mode, input, output );
00159 
00160             for( i = 0; i < 8; i++ )
00161                 output[i] = (unsigned char)( output[i] ^ iv[i] );
00162 
00163             memcpy( iv, temp, 8 );
00164 
00165             input  += 8;
00166             output += 8;
00167             length -= 8;
00168         }
00169     }
00170     else
00171     {
00172         while( length > 0 )
00173         {
00174             for( i = 0; i < 8; i++ )
00175                 output[i] = (unsigned char)( input[i] ^ iv[i] );
00176 
00177             mbedtls_xtea_crypt_ecb( ctx, mode, output, output );
00178             memcpy( iv, output, 8 );
00179 
00180             input  += 8;
00181             output += 8;
00182             length -= 8;
00183         }
00184     }
00185 
00186     return( 0 );
00187 }
00188 #endif /* MBEDTLS_CIPHER_MODE_CBC */
00189 #endif /* !MBEDTLS_XTEA_ALT */
00190 
00191 #if defined(MBEDTLS_SELF_TEST)
00192 
00193 /*
00194  * XTEA tests vectors (non-official)
00195  */
00196 
00197 static const unsigned char xtea_test_key[6][16] =
00198 {
00199    { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
00200      0x0c, 0x0d, 0x0e, 0x0f },
00201    { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
00202      0x0c, 0x0d, 0x0e, 0x0f },
00203    { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
00204      0x0c, 0x0d, 0x0e, 0x0f },
00205    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
00206      0x00, 0x00, 0x00, 0x00 },
00207    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
00208      0x00, 0x00, 0x00, 0x00 },
00209    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
00210      0x00, 0x00, 0x00, 0x00 }
00211 };
00212 
00213 static const unsigned char xtea_test_pt[6][8] =
00214 {
00215     { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
00216     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
00217     { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
00218     { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
00219     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
00220     { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
00221 };
00222 
00223 static const unsigned char xtea_test_ct[6][8] =
00224 {
00225     { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
00226     { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
00227     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
00228     { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
00229     { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
00230     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
00231 };
00232 
00233 /*
00234  * Checkup routine
00235  */
00236 int mbedtls_xtea_self_test( int verbose )
00237 {
00238     int i, ret = 0;
00239     unsigned char buf[8];
00240     mbedtls_xtea_context ctx;
00241 
00242     mbedtls_xtea_init( &ctx );
00243     for( i = 0; i < 6; i++ )
00244     {
00245         if( verbose != 0 )
00246             mbedtls_printf( "  XTEA test #%d: ", i + 1 );
00247 
00248         memcpy( buf, xtea_test_pt[i], 8 );
00249 
00250         mbedtls_xtea_setup( &ctx, xtea_test_key[i] );
00251         mbedtls_xtea_crypt_ecb( &ctx, MBEDTLS_XTEA_ENCRYPT, buf, buf );
00252 
00253         if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 )
00254         {
00255             if( verbose != 0 )
00256                 mbedtls_printf( "failed\n" );
00257 
00258             ret = 1;
00259             goto exit;
00260         }
00261 
00262         if( verbose != 0 )
00263             mbedtls_printf( "passed\n" );
00264     }
00265 
00266     if( verbose != 0 )
00267         mbedtls_printf( "\n" );
00268 
00269 exit:
00270     mbedtls_xtea_free( &ctx );
00271 
00272     return( ret );
00273 }
00274 
00275 #endif /* MBEDTLS_SELF_TEST */
00276 
00277 #endif /* MBEDTLS_XTEA_C */