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 
00032 #include <string.h>
00033 
00034 #if defined(MBEDTLS_SELF_TEST)
00035 #if defined(MBEDTLS_PLATFORM_C)
00036 #include "mbedtls/platform.h"
00037 #else
00038 #include <stdio.h>
00039 #define mbedtls_printf printf
00040 #endif /* MBEDTLS_PLATFORM_C */
00041 #endif /* MBEDTLS_SELF_TEST */
00042 
00043 #if !defined(MBEDTLS_XTEA_ALT)
00044 
00045 /* Implementation that should never be optimized out by the compiler */
00046 static void mbedtls_zeroize( void *v, size_t n ) {
00047     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
00048 }
00049 
00050 /*
00051  * 32-bit integer manipulation macros (big endian)
00052  */
00053 #ifndef GET_UINT32_BE
00054 #define GET_UINT32_BE(n,b,i)                            \
00055 {                                                       \
00056     (n) = ( (uint32_t) (b)[(i)    ] << 24 )             \
00057         | ( (uint32_t) (b)[(i) + 1] << 16 )             \
00058         | ( (uint32_t) (b)[(i) + 2] <<  8 )             \
00059         | ( (uint32_t) (b)[(i) + 3]       );            \
00060 }
00061 #endif
00062 
00063 #ifndef PUT_UINT32_BE
00064 #define PUT_UINT32_BE(n,b,i)                            \
00065 {                                                       \
00066     (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
00067     (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
00068     (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
00069     (b)[(i) + 3] = (unsigned char) ( (n)       );       \
00070 }
00071 #endif
00072 
00073 void mbedtls_xtea_init( mbedtls_xtea_context *ctx )
00074 {
00075     memset( ctx, 0, sizeof( mbedtls_xtea_context ) );
00076 }
00077 
00078 void mbedtls_xtea_free( mbedtls_xtea_context *ctx )
00079 {
00080     if( ctx == NULL )
00081         return;
00082 
00083     mbedtls_zeroize( ctx, sizeof( mbedtls_xtea_context ) );
00084 }
00085 
00086 /*
00087  * XTEA key schedule
00088  */
00089 void mbedtls_xtea_setup( mbedtls_xtea_context *ctx, const unsigned char key[16] )
00090 {
00091     int i;
00092 
00093     memset( ctx, 0, sizeof(mbedtls_xtea_context) );
00094 
00095     for( i = 0; i < 4; i++ )
00096     {
00097         GET_UINT32_BE( ctx->k [i], key, i << 2 );
00098     }
00099 }
00100 
00101 /*
00102  * XTEA encrypt function
00103  */
00104 int mbedtls_xtea_crypt_ecb( mbedtls_xtea_context *ctx, int mode,
00105                     const unsigned char input[8], unsigned char output[8])
00106 {
00107     uint32_t *k, v0, v1, i;
00108 
00109     k = ctx->k ;
00110 
00111     GET_UINT32_BE( v0, input, 0 );
00112     GET_UINT32_BE( v1, input, 4 );
00113 
00114     if( mode == MBEDTLS_XTEA_ENCRYPT )
00115     {
00116         uint32_t sum = 0, delta = 0x9E3779B9;
00117 
00118         for( i = 0; i < 32; i++ )
00119         {
00120             v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
00121             sum += delta;
00122             v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
00123         }
00124     }
00125     else /* MBEDTLS_XTEA_DECRYPT */
00126     {
00127         uint32_t delta = 0x9E3779B9, sum = delta * 32;
00128 
00129         for( i = 0; i < 32; i++ )
00130         {
00131             v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
00132             sum -= delta;
00133             v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
00134         }
00135     }
00136 
00137     PUT_UINT32_BE( v0, output, 0 );
00138     PUT_UINT32_BE( v1, output, 4 );
00139 
00140     return( 0 );
00141 }
00142 
00143 #if defined(MBEDTLS_CIPHER_MODE_CBC)
00144 /*
00145  * XTEA-CBC buffer encryption/decryption
00146  */
00147 int mbedtls_xtea_crypt_cbc( mbedtls_xtea_context *ctx, int mode, size_t length,
00148                     unsigned char iv[8], const unsigned char *input,
00149                     unsigned char *output)
00150 {
00151     int i;
00152     unsigned char temp[8];
00153 
00154     if( length % 8 )
00155         return( MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH );
00156 
00157     if( mode == MBEDTLS_XTEA_DECRYPT )
00158     {
00159         while( length > 0 )
00160         {
00161             memcpy( temp, input, 8 );
00162             mbedtls_xtea_crypt_ecb( ctx, mode, input, output );
00163 
00164             for( i = 0; i < 8; i++ )
00165                 output[i] = (unsigned char)( output[i] ^ iv[i] );
00166 
00167             memcpy( iv, temp, 8 );
00168 
00169             input  += 8;
00170             output += 8;
00171             length -= 8;
00172         }
00173     }
00174     else
00175     {
00176         while( length > 0 )
00177         {
00178             for( i = 0; i < 8; i++ )
00179                 output[i] = (unsigned char)( input[i] ^ iv[i] );
00180 
00181             mbedtls_xtea_crypt_ecb( ctx, mode, output, output );
00182             memcpy( iv, output, 8 );
00183 
00184             input  += 8;
00185             output += 8;
00186             length -= 8;
00187         }
00188     }
00189 
00190     return( 0 );
00191 }
00192 #endif /* MBEDTLS_CIPHER_MODE_CBC */
00193 #endif /* !MBEDTLS_XTEA_ALT */
00194 
00195 #if defined(MBEDTLS_SELF_TEST)
00196 
00197 /*
00198  * XTEA tests vectors (non-official)
00199  */
00200 
00201 static const unsigned char xtea_test_key[6][16] =
00202 {
00203    { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
00204      0x0c, 0x0d, 0x0e, 0x0f },
00205    { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
00206      0x0c, 0x0d, 0x0e, 0x0f },
00207    { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
00208      0x0c, 0x0d, 0x0e, 0x0f },
00209    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
00210      0x00, 0x00, 0x00, 0x00 },
00211    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
00212      0x00, 0x00, 0x00, 0x00 },
00213    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
00214      0x00, 0x00, 0x00, 0x00 }
00215 };
00216 
00217 static const unsigned char xtea_test_pt[6][8] =
00218 {
00219     { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
00220     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
00221     { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
00222     { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
00223     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
00224     { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
00225 };
00226 
00227 static const unsigned char xtea_test_ct[6][8] =
00228 {
00229     { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
00230     { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
00231     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
00232     { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
00233     { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
00234     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
00235 };
00236 
00237 /*
00238  * Checkup routine
00239  */
00240 int mbedtls_xtea_self_test( int verbose )
00241 {
00242     int i, ret = 0;
00243     unsigned char buf[8];
00244     mbedtls_xtea_context ctx;
00245 
00246     mbedtls_xtea_init( &ctx );
00247     for( i = 0; i < 6; i++ )
00248     {
00249         if( verbose != 0 )
00250             mbedtls_printf( "  XTEA test #%d: ", i + 1 );
00251 
00252         memcpy( buf, xtea_test_pt[i], 8 );
00253 
00254         mbedtls_xtea_setup( &ctx, xtea_test_key[i] );
00255         mbedtls_xtea_crypt_ecb( &ctx, MBEDTLS_XTEA_ENCRYPT, buf, buf );
00256 
00257         if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 )
00258         {
00259             if( verbose != 0 )
00260                 mbedtls_printf( "failed\n" );
00261 
00262             ret = 1;
00263             goto exit;
00264         }
00265 
00266         if( verbose != 0 )
00267             mbedtls_printf( "passed\n" );
00268     }
00269 
00270     if( verbose != 0 )
00271         mbedtls_printf( "\n" );
00272 
00273 exit:
00274     mbedtls_xtea_free( &ctx );
00275 
00276     return( ret );
00277 }
00278 
00279 #endif /* MBEDTLS_SELF_TEST */
00280 
00281 #endif /* MBEDTLS_XTEA_C */