/* * An 32-bit implementation of the XTEA algorithm * * Copyright (C) 2006-2014, ARM Limited, All Rights Reserved * * This file is part of mbed TLS (http://www.polarssl.org) * Lead Maintainer: Paul Bakker * * 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. */ #if !defined(POLARSSL_CONFIG_FILE) #include "polarssl/config.h" #else #include POLARSSL_CONFIG_FILE #endif #if defined(POLARSSL_XTEA_C) #include "polarssl/xtea.h" #if defined(POLARSSL_PLATFORM_C) #include "polarssl/platform.h" #else #define polarssl_printf printf #endif #if !defined(POLARSSL_XTEA_ALT) /* Implementation that should never be optimized out by the compiler */ static void polarssl_zeroize( void *v, size_t n ) { volatile unsigned char *p = v; while( n-- ) *p++ = 0; } /* * 32-bit integer manipulation macros (big endian) */ #ifndef GET_UINT32_BE #define GET_UINT32_BE(n,b,i) \ { \ (n) = ( (uint32_t) (b)[(i) ] << 24 ) \ | ( (uint32_t) (b)[(i) + 1] << 16 ) \ | ( (uint32_t) (b)[(i) + 2] << 8 ) \ | ( (uint32_t) (b)[(i) + 3] ); \ } #endif #ifndef PUT_UINT32_BE #define PUT_UINT32_BE(n,b,i) \ { \ (b)[(i) ] = (unsigned char) ( (n) >> 24 ); \ (b)[(i) + 1] = (unsigned char) ( (n) >> 16 ); \ (b)[(i) + 2] = (unsigned char) ( (n) >> 8 ); \ (b)[(i) + 3] = (unsigned char) ( (n) ); \ } #endif void xtea_init( xtea_context *ctx ) { memset( ctx, 0, sizeof( xtea_context ) ); } void xtea_free( xtea_context *ctx ) { if( ctx == NULL ) return; polarssl_zeroize( ctx, sizeof( xtea_context ) ); } /* * XTEA key schedule */ void xtea_setup( xtea_context *ctx, const unsigned char key[16] ) { int i; memset( ctx, 0, sizeof(xtea_context) ); for( i = 0; i < 4; i++ ) { GET_UINT32_BE( ctx->k[i], key, i << 2 ); } } /* * XTEA encrypt function */ int xtea_crypt_ecb( xtea_context *ctx, int mode, const unsigned char input[8], unsigned char output[8]) { uint32_t *k, v0, v1, i; k = ctx->k; GET_UINT32_BE( v0, input, 0 ); GET_UINT32_BE( v1, input, 4 ); if( mode == XTEA_ENCRYPT ) { uint32_t sum = 0, delta = 0x9E3779B9; for( i = 0; i < 32; i++ ) { v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]); sum += delta; v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]); } } else /* XTEA_DECRYPT */ { uint32_t delta = 0x9E3779B9, sum = delta * 32; for( i = 0; i < 32; i++ ) { v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]); sum -= delta; v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]); } } PUT_UINT32_BE( v0, output, 0 ); PUT_UINT32_BE( v1, output, 4 ); return( 0 ); } #if defined(POLARSSL_CIPHER_MODE_CBC) /* * XTEA-CBC buffer encryption/decryption */ int xtea_crypt_cbc( xtea_context *ctx, int mode, size_t length, unsigned char iv[8], const unsigned char *input, unsigned char *output) { int i; unsigned char temp[8]; if( length % 8 ) return( POLARSSL_ERR_XTEA_INVALID_INPUT_LENGTH ); if( mode == XTEA_DECRYPT ) { while( length > 0 ) { memcpy( temp, input, 8 ); xtea_crypt_ecb( ctx, mode, input, output ); for( i = 0; i < 8; i++ ) output[i] = (unsigned char)( output[i] ^ iv[i] ); memcpy( iv, temp, 8 ); input += 8; output += 8; length -= 8; } } else { while( length > 0 ) { for( i = 0; i < 8; i++ ) output[i] = (unsigned char)( input[i] ^ iv[i] ); xtea_crypt_ecb( ctx, mode, output, output ); memcpy( iv, output, 8 ); input += 8; output += 8; length -= 8; } } return( 0 ); } #endif /* POLARSSL_CIPHER_MODE_CBC */ #endif /* !POLARSSL_XTEA_ALT */ #if defined(POLARSSL_SELF_TEST) #include #include /* * XTEA tests vectors (non-official) */ static const unsigned char xtea_test_key[6][16] = { { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }, { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }, { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }, { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }; static const unsigned char xtea_test_pt[6][8] = { { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 }, { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }, { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f }, { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 }, { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }, { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 } }; static const unsigned char xtea_test_ct[6][8] = { { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 }, { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 }, { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }, { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 }, { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d }, { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 } }; /* * Checkup routine */ int xtea_self_test( int verbose ) { int i, ret = 0; unsigned char buf[8]; xtea_context ctx; xtea_init( &ctx ); for( i = 0; i < 6; i++ ) { if( verbose != 0 ) polarssl_printf( " XTEA test #%d: ", i + 1 ); memcpy( buf, xtea_test_pt[i], 8 ); xtea_setup( &ctx, xtea_test_key[i] ); xtea_crypt_ecb( &ctx, XTEA_ENCRYPT, buf, buf ); if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 ) { if( verbose != 0 ) polarssl_printf( "failed\n" ); ret = 1; goto exit; } if( verbose != 0 ) polarssl_printf( "passed\n" ); } if( verbose != 0 ) polarssl_printf( "\n" ); exit: xtea_free( &ctx ); return( ret ); } #endif /* POLARSSL_SELF_TEST */ #endif /* POLARSSL_XTEA_C */