library/cmac.c - security/mbedtls - Rivoreo Source Code Repositories

 /*
  *  NIST SP800-38B compliant CMAC implementation
  *
  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
  *  SPDX-License-Identifier: Apache-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.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
  */

 /*
  * Definition of CMAC:
  * http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf
  * RFC 4493 "The AES-CMAC Algorithm"
  */

 #if !defined(MBEDTLS_CONFIG_FILE)
 #include "mbedtls/config.h"
 #else
 #include MBEDTLS_CONFIG_FILE
 #endif

 #if defined(MBEDTLS_CMAC_C)

 #include "mbedtls/cmac.h"

 #include <string.h>

 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 #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 && MBEDTLS_AES_C */

 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
 }

 /*
  * Initialize context
  */
 void mbedtls_cmac_init( mbedtls_cmac_context *ctx )
 {
     memset( ctx, 0, sizeof( mbedtls_cmac_context ) );
 }


 /*
  * Multiplication by u in the Galois field of GF(2^n)
  *
  * As explained in the paper, this can computed:
  * If MSB(p) = 0, then p = (p << 1)
  * If MSB(p) = 1, then p = (p << 1) ^ R_n
  * with R_64 = 0x1B and  R_128 = 0x87
  *
  * Input and output MUST not point to the same buffer
  * Block size must be 8 byes or 16 bytes.
  */
 static int cmac_multiply_by_u( unsigned char *output,
                                const unsigned char *input,
 							   size_t blocksize )
 {

     const unsigned char R_128 = 0x87;
     const unsigned char R_64 = 0x1B;
     unsigned char R_n, mask;
     unsigned char overflow = 0x00;
     int i, starting_index;

     starting_index = blocksize -1;

     if( blocksize == 16 ){
         R_n = R_128;
     } else if( blocksize == 8 ) {
         R_n = R_64;
     } else {
         return( MBEDTLS_ERR_CMAC_BAD_INPUT );
     }


     for( i = starting_index; i >= 0; i-- )
     {
         output[i] = input[i] << 1 | overflow;
         overflow = input[i] >> 7;
     }

     /* mask = ( input[0] >> 7 ) ? 0xff : 0x00
      * using bit operations to avoid branches */
     /* MSVC has a warning about unary minus on unsigned, but this is
      * well-defined and precisely what we want to do here */
 #if defined(_MSC_VER)
 #pragma warning( push )
 #pragma warning( disable : 4146 )
 #endif
     mask = - ( input[0] >> 7 );
 #if defined(_MSC_VER)
 #pragma warning( pop )
 #endif

     output[starting_index] ^= R_n & mask;
     return( 0 );
 }

 /*
  * Generate subkeys
  */
 static int cmac_generate_subkeys( mbedtls_cmac_context *ctx )
 {
     int ret, keybytes;
     unsigned char *L;
     size_t olen, block_size;

     ret = 0;
     block_size = ctx->cipher_ctx.cipher_info->block_size;

     L = mbedtls_calloc( block_size, sizeof( unsigned char ) );

     /* Calculate Ek(0) */
     memset( L, 0, block_size );
     if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx,
                                        L, block_size, L, &olen ) ) != 0 )
     {
         goto exit;
     }

     /*
      * Generate K1 and K2
      */
     if( ( ret = cmac_multiply_by_u( ctx->K1, L , block_size ) ) != 0 )
         goto exit;
     if( ( cmac_multiply_by_u( ctx->K2, ctx->K1 , block_size ) ) != 0 )
         goto exit;

     exit:
         mbedtls_zeroize( L, sizeof( L ) );
 		free( L );
         return( ret );
 }

 /*
  * Set key and prepare context for use
  */
 int mbedtls_cmac_setkey( mbedtls_cmac_context *ctx,
                          mbedtls_cipher_id_t cipher,
                          const unsigned char *key,
                          unsigned int keybits )
 {
     int ret, blocksize;
     const mbedtls_cipher_info_t *cipher_info;

     cipher_info = mbedtls_cipher_info_from_values( cipher, keybits,
                                                    MBEDTLS_MODE_ECB );
     if( cipher_info == NULL )
         return( MBEDTLS_ERR_CMAC_BAD_INPUT );

     ctx->K1 = mbedtls_calloc( cipher_info->block_size, sizeof( unsigned char ) );
     ctx->K2 = mbedtls_calloc( cipher_info->block_size, sizeof( unsigned char ) );

     mbedtls_cipher_free( &ctx->cipher_ctx );

     if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
         return( ret );

     if( ( ret = mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits,
                                        MBEDTLS_ENCRYPT ) ) != 0 )
     {
         return( ret );
     }

     return( cmac_generate_subkeys( ctx ) );
 }

 /*
  * Free context
  */
 void mbedtls_cmac_free( mbedtls_cmac_context *ctx )
 {
 	int block_size;
 	block_size = ctx->cipher_ctx.cipher_info->block_size;

     mbedtls_cipher_free( &ctx->cipher_ctx );

     mbedtls_zeroize( ctx->K1, block_size * sizeof( unsigned char ) );
     mbedtls_zeroize( ctx->K2, block_size * sizeof( unsigned char ) );
     mbedtls_free( ctx->K1 );
     mbedtls_free( ctx->K2 );
 }

 /*
  * Create padded last block from (partial) last block.
  *
  * We can't use the padding option from the cipher layer, as it only works for
  * CBC and we use ECB mode, and anyway we need to XOR K1 or K2 in addition.
  */
 static void cmac_pad( unsigned char padded_block[16],
 		              size_t padded_block_len,
                       const unsigned char *last_block,
                       size_t last_block_len )
 {
     size_t j;

     for( j = 0; j < padded_block_len; j++ )
     {
         if( j < last_block_len )
             padded_block[j] = last_block[j];
         else if( j == last_block_len )
             padded_block[j] = 0x80;
         else
             padded_block[j] = 0x00;
     }
 }

 /*
  * XOR Block
  * Here, macro results in smaller compiled code than static inline function
  */
 #define XOR_BLOCK( o, i1, i2 )                                                \
     for( i = 0; i < block_size; i++ )                                         \
         ( o )[i] = ( i1 )[i] ^ ( i2 )[i];

 /*
  * Update the CMAC state using an input block x
  */
 #define UPDATE_CMAC( x )                                                    \
 do {                                                                        \
     XOR_BLOCK( state, ( x ), state );                                       \
     if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx,                    \
                                        state, block_size,                   \
                                        state, &olen ) ) != 0 )              \
         return( ret );                                                      \
 } while( 0 )

 /*
  * Generate tag on complete message
  */
 int mbedtls_cmac_generate( mbedtls_cmac_context *ctx,
                            const unsigned char *input, size_t in_len,
                            unsigned char *tag, size_t tag_len )

 {

     unsigned char *state;
     unsigned char *M_last;
     int     n, i, j, ret, needs_padding;
     size_t olen, block_size;


     ret = 0;
     block_size = ctx->cipher_ctx.cipher_info->block_size;

     state = mbedtls_calloc( block_size,  sizeof( unsigned char ) );
     M_last = mbedtls_calloc( block_size, sizeof( unsigned char ) );

     /*
      * Check in_len requirements: SP800-38B A
      * 4 is a worst case bottom limit
      */
     if( tag_len < 4 || tag_len > block_size || tag_len % 2 != 0 )
         return( MBEDTLS_ERR_CMAC_BAD_INPUT );

     if( in_len == 0 )
         needs_padding = 1;
     else
         needs_padding = in_len % block_size != 0;

     n = in_len / block_size + needs_padding;

     /* Calculate last block */
     if( needs_padding )
     {
         cmac_pad( M_last, block_size, input + block_size * ( n - 1 ), in_len % block_size );
         XOR_BLOCK( M_last, M_last, ctx->K2 );
     }
     else
     {
         /* Last block is complete block */
         XOR_BLOCK( M_last, input + block_size * ( n - 1 ), ctx->K1 );
     }

     memset( state, 0, block_size );

     for( j = 0; j < n - 1; j++ )
         UPDATE_CMAC( input + block_size * j );

     UPDATE_CMAC( M_last );

     memcpy( tag, state, tag_len );

     exit:
         free( state );
         free( M_last );
         return( ret );
 }

 #undef XOR_BLOCK
 #undef UPDATE_CMAC

 /*
  * Verify tag on complete message
  */
 int mbedtls_cmac_verify( mbedtls_cmac_context *ctx,
                          const unsigned char *input, size_t in_len,
                          const unsigned char *tag, size_t tag_len )
 {
     int ret;
     unsigned char *check_tag;
     unsigned char i;
     int diff;

     check_tag = mbedtls_calloc( ctx->cipher_ctx.cipher_info->block_size,
                                 sizeof( unsigned char ) );

     if( ( ret = mbedtls_cmac_generate( ctx, input, in_len,
                                        check_tag, tag_len ) ) != 0 )
     {
         goto exit;
     }

     /* Check tag in "constant-time" */
     for( diff = 0, i = 0; i < tag_len; i++ )
         diff |= tag[i] ^ check_tag[i];

     if( diff != 0 )
         ret = MBEDTLS_ERR_CMAC_VERIFY_FAILED;
         goto exit;

     exit:
 	    free( check_tag );
         return( ret );
 }

 #ifdef MBEDTLS_AES_C
 /*
  * PRF based on CMAC with AES-128
  * See RFC 4615
  */
 int mbedtls_aes_cmac_prf_128( const unsigned char *key, size_t key_length,
                               const unsigned char *input, size_t in_len,
                               unsigned char tag[16] )
 {
     int ret;
     mbedtls_cmac_context ctx;
     unsigned char zero_key[16];
     unsigned char int_key[16];

     mbedtls_cmac_init(&ctx );

     if( key_length == 16 )
     {
         /* Use key as is */
         memcpy( int_key, key, 16 );
     }
     else
     {
         mbedtls_cmac_context zero_ctx;

         /* Key is AES_CMAC( 0, key ) */
         mbedtls_cmac_init( &zero_ctx );
         memset( zero_key, 0, 16 );
         ret = mbedtls_cmac_setkey( &zero_ctx, MBEDTLS_CIPHER_ID_AES,
                                    zero_key, 8 * sizeof zero_key );
         if( ret != 0 )
             goto exit;

         ret = mbedtls_cmac_generate( &zero_ctx, key, key_length, int_key, 16 );
         if( ret != 0 )
             goto exit;
     }

     ret = mbedtls_cmac_setkey( &ctx, MBEDTLS_CIPHER_ID_AES,
                                int_key, 8 * sizeof int_key );
     if( ret != 0 )
         goto exit;

     mbedtls_zeroize( int_key, sizeof( int_key ) );

     ret =  mbedtls_cmac_generate( &ctx, input, in_len, tag, 16 );

     exit:
 	     mbedtls_cmac_free( &ctx );
 	     return( ret );
 }
 #endif /* MBEDTLS_AES_C */

 #ifdef MBEDTLS_SELF_TEST
 /*
  * CMAC test data from SP800-38B Appendix D.1 (corrected)
  * http://csrc.nist.gov/publications/nistpubs/800-38B/Updated_CMAC_Examples.pdf
  *
  * AES-CMAC-PRF-128 test data from RFC 4615
  * https://tools.ietf.org/html/rfc4615#page-4
  */

 #define NB_CMAC_TESTS_PER_KEY 4
 #define NB_PRF_TESTS 3
 #define AES_BLOCK_SIZE 16
 #define DES3_BLOCK_SIZE 8

 #if defined(MBEDTLS_AES_C) || defined(MBEDTLS_DES_C)
 /* All CMAC test inputs are truncated from the same 64 byte buffer. */
 static const unsigned char test_message[] = {
     0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
     0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
     0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
     0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
     0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
     0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
     0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
     0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10
 };
 #endif /* defined(MBEDTLS_AES_C) || defined(MBEDTLS_DES_C) */

 #ifdef MBEDTLS_AES_C
 /* Truncation point of message for AES CMAC tests  */
 static const size_t aes_message_lengths[NB_CMAC_TESTS_PER_KEY] = {
     0,
     16,
     40,
     64
 };

 /* AES 128 CMAC Test Data */
 static const unsigned char aes_128_key[] = {
     0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
     0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c
 };
 static const unsigned char aes_128_subkeys[2][AES_BLOCK_SIZE] = {
     {
         0xfb, 0xee, 0xd6, 0x18, 0x35, 0x71, 0x33, 0x66,
         0x7c, 0x85, 0xe0, 0x8f, 0x72, 0x36, 0xa8, 0xde
     },
     {
         0xf7, 0xdd, 0xac, 0x30, 0x6a, 0xe2, 0x66, 0xcc,
         0xf9, 0x0b, 0xc1, 0x1e, 0xe4, 0x6d, 0x51, 0x3b
     }
 };
 static const unsigned char aes_128_expected_result[NB_CMAC_TESTS_PER_KEY][AES_BLOCK_SIZE] = {
     {
         0xbb, 0x1d, 0x69, 0x29, 0xe9, 0x59, 0x37, 0x28,
         0x7f, 0xa3, 0x7d, 0x12, 0x9b, 0x75, 0x67, 0x46
     },
     {
         0x07, 0x0a, 0x16, 0xb4, 0x6b, 0x4d, 0x41, 0x44,
         0xf7, 0x9b, 0xdd, 0x9d, 0xd0, 0x4a, 0x28, 0x7c
     },
     {
         0xdf, 0xa6, 0x67, 0x47, 0xde, 0x9a, 0xe6, 0x30,
         0x30, 0xca, 0x32, 0x61, 0x14, 0x97, 0xc8, 0x27
     },
     {
         0x51, 0xf0, 0xbe, 0xbf, 0x7e, 0x3b, 0x9d, 0x92,
         0xfc, 0x49, 0x74, 0x17, 0x79, 0x36, 0x3c, 0xfe
     }
 };

 /* AES 192 CMAC Test Data */
 static const unsigned char aes_192_key[] = {
 		0x8e, 0x73, 0xb0, 0xf7, 0xda, 0x0e, 0x64, 0x52,
 		0xc8, 0x10, 0xf3, 0x2b, 0x80, 0x90, 0x79, 0xe5,
 		0x62, 0xf8, 0xea, 0xd2, 0x52, 0x2c, 0x6b, 0x7b
 };
 static const unsigned char aes_192_subkeys[2][AES_BLOCK_SIZE] = {
     {
         0x44, 0x8a, 0x5b, 0x1c, 0x93, 0x51, 0x4b, 0x27,
         0x3e, 0xe6, 0x43, 0x9d, 0xd4, 0xda, 0xa2, 0x96
     },
     {
         0x89, 0x14, 0xb6, 0x39, 0x26, 0xa2, 0x96, 0x4e,
         0x7d, 0xcc, 0x87, 0x3b, 0xa9, 0xb5, 0x45, 0x2c
     }
 };
 static const unsigned char aes_192_expected_result[NB_CMAC_TESTS_PER_KEY][AES_BLOCK_SIZE] = {
     {
         0xd1, 0x7d, 0xdf, 0x46, 0xad, 0xaa, 0xcd, 0xe5,
         0x31, 0xca, 0xc4, 0x83, 0xde, 0x7a, 0x93, 0x67
     },
     {
         0x9e, 0x99, 0xa7, 0xbf, 0x31, 0xe7, 0x10, 0x90,
         0x06, 0x62, 0xf6, 0x5e, 0x61, 0x7c, 0x51, 0x84
     },
     {
         0x8a, 0x1d, 0xe5, 0xbe, 0x2e, 0xb3, 0x1a, 0xad,
         0x08, 0x9a, 0x82, 0xe6, 0xee, 0x90, 0x8b, 0x0e
     },
     {
         0xa1, 0xd5, 0xdf, 0x0e, 0xed, 0x79, 0x0f, 0x79,
         0x4d, 0x77, 0x58, 0x96, 0x59, 0xf3, 0x9a, 0x11
     }
 };

 /* AES 256 CMAC Test Data */
 static const unsigned char aes_256_key[] = {
 		0x60, 0x3d, 0xeb, 0x10, 0x15, 0xca, 0x71, 0xbe,
 		0x2b, 0x73, 0xae, 0xf0, 0x85, 0x7d, 0x77, 0x81,
 		0x1f, 0x35, 0x2c, 0x07, 0x3b, 0x61, 0x08, 0xd7,
 		0x2d, 0x98, 0x10, 0xa3, 0x09, 0x14, 0xdf, 0xf4
 };
 static const unsigned char aes_256_subkeys[2][AES_BLOCK_SIZE] = {
     {
         0xca, 0xd1, 0xed, 0x03, 0x29, 0x9e, 0xed, 0xac,
         0x2e, 0x9a, 0x99, 0x80, 0x86, 0x21, 0x50, 0x2f
     },
     {
         0x95, 0xa3, 0xda, 0x06, 0x53, 0x3d, 0xdb, 0x58,
         0x5d, 0x35, 0x33, 0x01, 0x0c, 0x42, 0xa0, 0xd9
     }
 };
 static const unsigned char aes_256_expected_result[NB_CMAC_TESTS_PER_KEY][AES_BLOCK_SIZE] = {
     {
         0x02, 0x89, 0x62, 0xf6, 0x1b, 0x7b, 0xf8, 0x9e,
         0xfc, 0x6b, 0x55, 0x1f, 0x46, 0x67, 0xd9, 0x83
     },
     {
         0x28, 0xa7, 0x02, 0x3f, 0x45, 0x2e, 0x8f, 0x82,
         0xbd, 0x4b, 0xf2, 0x8d, 0x8c, 0x37, 0xc3, 0x5c
     },
     {
         0xaa, 0xf3, 0xd8, 0xf1, 0xde, 0x56, 0x40, 0xc2,
         0x32, 0xf5, 0xb1, 0x69, 0xb9, 0xc9, 0x11, 0xe6
     },
     {
         0xe1, 0x99, 0x21, 0x90, 0x54, 0x9f, 0x6e, 0xd5,
         0x69, 0x6a, 0x2c, 0x05, 0x6c, 0x31, 0x54, 0x10
     }
 };
 #endif /* MBEDTLS_AES_C */

 #ifdef MBEDTLS_DES_C
 /* Truncation point of message for 3DES CMAC tests  */
 static const size_t des3_message_lengths[NB_CMAC_TESTS_PER_KEY] = {
     0,
     8,
     20,
     32
 };

 /* 3DES 2 Key CMAC Test Data */
 static const unsigned char des3_2key_key[] = {
 		0x4c, 0xf1, 0x51, 0x34, 0xa2, 0x85, 0x0d, 0xd5,
 		0x8a, 0x3d, 0x10, 0xba, 0x80, 0x57, 0x0d, 0x38,
 		0x4c, 0xf1, 0x51, 0x34, 0xa2, 0x85, 0x0d, 0xd5
 };
 static const unsigned char des3_2key_subkeys[2][8] = {
     {
         0x8e, 0xcf, 0x37, 0x3e, 0xd7, 0x1a, 0xfa, 0xef
     },
     {
         0x1d, 0x9e, 0x6e, 0x7d, 0xae, 0x35, 0xf5, 0xc5
     }
 };
 static const unsigned char T_3des_2key[NB_CMAC_TESTS_PER_KEY][DES3_BLOCK_SIZE] = {
     {
         0xbd, 0x2e, 0xbf, 0x9a, 0x3b, 0xa0, 0x03, 0x61
     },
     {
         0x4f, 0xf2, 0xab, 0x81, 0x3c, 0x53, 0xce, 0x83
     },
     {
         0x62, 0xdd, 0x1b, 0x47, 0x19, 0x02, 0xbd, 0x4e
     },
     {
         0x31, 0xb1, 0xe4, 0x31, 0xda, 0xbc, 0x4e, 0xb8
     }
 };

 /* 3DES 3 Key CMAC Test Data */
 static const unsigned char des3_3key_key[] = {
 		0x8a, 0xa8, 0x3b, 0xf8, 0xcb, 0xda, 0x10, 0x62,
 		0x0b, 0xc1, 0xbf, 0x19, 0xfb, 0xb6, 0xcd, 0x58,
 		0xbc, 0x31, 0x3d, 0x4a, 0x37, 0x1c, 0xa8, 0xb5
 };
 static const unsigned char des3_3key_subkeys[2][8] = {
     {
         0x91, 0x98, 0xe9, 0xd3, 0x14, 0xe6, 0x53, 0x5f
     },
     {
         0x23, 0x31, 0xd3, 0xa6, 0x29, 0xcc, 0xa6, 0xa5
     }
 };
 static const unsigned char T_3des_3key[NB_CMAC_TESTS_PER_KEY][DES3_BLOCK_SIZE] = {
     {
         0xb7, 0xa6, 0x88, 0xe1, 0x22, 0xff, 0xaf, 0x95
     },
     {
         0x8e, 0x8f, 0x29, 0x31, 0x36, 0x28, 0x37, 0x97
     },
     {
         0x74, 0x3d, 0xdb, 0xe0, 0xce, 0x2d, 0xc2, 0xed
     },
     {
         0x33, 0xe6, 0xb1, 0x09, 0x24, 0x00, 0xea, 0xe5
     }
 };

 #endif /* MBEDTLS_DES_C */

 #ifdef MBEDTLS_AES_C
 /* AES AES-CMAC-PRF-128 Test Data */
 static const unsigned char PRFK[] = {
     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
     0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
     0xed, 0xcb
 };

 /* Sizes in bytes */
 static const size_t PRFKlen[NB_PRF_TESTS] = {
     18,
     16,
     10
 };

 /* PRF M */
 static const unsigned char PRFM[] = {
     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
     0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
     0x10, 0x11, 0x12, 0x13
 };

 static const unsigned char PRFT[NB_PRF_TESTS][16] = {
     {
         0x84, 0xa3, 0x48, 0xa4, 0xa4, 0x5d, 0x23, 0x5b,
         0xab, 0xff, 0xfc, 0x0d, 0x2b, 0x4d, 0xa0, 0x9a
     },
     {
         0x98, 0x0a, 0xe8, 0x7b, 0x5f, 0x4c, 0x9c, 0x52,
         0x14, 0xf5, 0xb6, 0xa8, 0x45, 0x5e, 0x4c, 0x2d
     },
     {
         0x29, 0x0d, 0x9e, 0x11, 0x2e, 0xdb, 0x09, 0xee,
         0x14, 0x1f, 0xcf, 0x64, 0xc0, 0xb7, 0x2f, 0x3d
     }
 };
 #endif /* MBEDTLS_AES_C */

 int test_cmac_with_cipher( int verbose,
 		                  const unsigned char* testname,
 		                  const unsigned char* key,
 		                  int keybits,
 		                  const unsigned char* messages,
 		                  size_t message_lengths[4],
 						  const unsigned char* subkeys,
 						  const unsigned char* expected_result,
 						  mbedtls_cipher_id_t cipher_id,
 						  int block_size )
 {
 	const int num_tests = 4;
 	mbedtls_cmac_context ctx;
     int i, ret;
     unsigned char* tag;

     tag = mbedtls_calloc( block_size, sizeof( unsigned char ) );
     mbedtls_cmac_init( &ctx );

     if( ( ret = mbedtls_cmac_setkey( &ctx, cipher_id, key, keybits ) ) != 0 )
     {
         if( verbose != 0 )
             mbedtls_printf( "  CMAC: setup failed\n" );
         goto exit;
     }

     if( ( ret = memcmp( ctx.K1, subkeys, block_size ) != 0 ) ||
         ( ret = memcmp( ctx.K2, &subkeys[block_size], block_size ) != 0 ) )
     {
         if( verbose != 0 )
             mbedtls_printf( "  CMAC: subkey generation failed\n" );
         goto exit;
     }

     for( i = 0; i < num_tests; i++ )
     {
         if( verbose != 0 )
             mbedtls_printf( "  %s CMAC #%u: ", testname, i +1 );

         if( ( ret = mbedtls_cmac_generate( &ctx, messages, message_lengths[i], tag, block_size ) ) != 0 )
         {
             if( verbose != 0 )
                 mbedtls_printf( "failed\n" );
             goto exit;
         }
         if( ( ret = memcmp( tag, &expected_result[i * block_size], block_size ) ) != 0 )
         {
             if( verbose != 0 )
                 mbedtls_printf( "failed\n" );
             goto exit;
         }

         if( ( ret = mbedtls_cmac_verify( &ctx, messages, message_lengths[i], &expected_result[i * block_size], block_size ) != 0 ) )
         {
                 if( verbose != 0 )
                     mbedtls_printf( "failed\n" );
                 goto exit;
         }
         mbedtls_printf( "passed\n" );
     }
     exit:
         free( tag );
         mbedtls_cmac_free( &ctx );
         return( ret );
 }

 #ifdef MBEDTLS_AES_C
 int test_aes128_cmac_prf( verbose ) {
     int i;
     int ret;
     unsigned char tag[16];
     for( i = 0; i < NB_PRF_TESTS; i++ )
     {
         mbedtls_printf( "  AES CMAC 128 PRF #%u: ", i );
         ret = mbedtls_aes_cmac_prf_128( PRFK, PRFKlen[i], PRFM, 20, tag );
         if( ret != 0 ||
             memcmp( tag, PRFT[i], 16 ) != 0 )
         {
             if( verbose != 0 )
                 mbedtls_printf( "failed\n" );

             return( ret );
         } else if( verbose != 0 )
         {
             mbedtls_printf( "passed\n" );
         }
     }
     return( ret );
 }
 #endif /* MBEDTLS_AES_C */

 int mbedtls_cmac_self_test( int verbose )
 {
     int ret;

 #ifdef MBEDTLS_AES_C
     test_cmac_with_cipher( verbose,
                              "AES 128",
                               aes_128_key,
                               128,
                               test_message,
                               aes_message_lengths,
                               aes_128_subkeys,
                               aes_128_expected_result,
                               MBEDTLS_CIPHER_ID_AES,
                               AES_BLOCK_SIZE );

     test_cmac_with_cipher( verbose,
                              "AES 192",
                               aes_192_key,
                               192,
                               test_message,
                               aes_message_lengths,
                               aes_192_subkeys,
                               aes_192_expected_result,
                               MBEDTLS_CIPHER_ID_AES,
                               AES_BLOCK_SIZE );

     test_cmac_with_cipher ( verbose,
                              "AES 256",
                               aes_256_key,
                               256,
                               test_message,
                               aes_message_lengths,
                               aes_256_subkeys,
                               aes_256_expected_result,
                               MBEDTLS_CIPHER_ID_AES,
                               AES_BLOCK_SIZE );
 #endif /* MBEDTLS_AES_C */

 #ifdef MBEDTLS_DES_C
     test_cmac_with_cipher( verbose,
                              "3DES 2 key",
                               des3_2key_key,
                               192,
                               test_message,
                               des3_message_lengths,
                               des3_2key_subkeys,
                               T_3des_2key,
                               MBEDTLS_CIPHER_ID_3DES,
                               DES3_BLOCK_SIZE );

     test_cmac_with_cipher( verbose,
                              "3DES 3 key",
                               des3_3key_key,
                               192,
                               test_message,
                               des3_message_lengths,
                               des3_3key_subkeys,
                               T_3des_3key,
                               MBEDTLS_CIPHER_ID_3DES,
                               DES3_BLOCK_SIZE );
 #endif /* MBEDTLS_DES_C */

 #ifdef MBEDTLS_AES_C
     test_aes128_cmac_prf( verbose );
 #endif /* MBEDTLS_AES_C */

     if( verbose != 0 )
         mbedtls_printf( "\n" );

     return( 0 );
 }

 #endif /* MBEDTLS_SELF_TEST */

 #endif /* MBEDTLS_CMAC_C */
	/*
	* NIST SP800-38B compliant CMAC implementation
	*
	* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
	* SPDX-License-Identifier: Apache-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.
	*
	* This file is part of mbed TLS (https://tls.mbed.org)
	*/

	/*
	* Definition of CMAC:
	* http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf
	* RFC 4493 "The AES-CMAC Algorithm"
	*/

	#if !defined(MBEDTLS_CONFIG_FILE)
	#include "mbedtls/config.h"
	#else
	#include MBEDTLS_CONFIG_FILE
	#endif

	#if defined(MBEDTLS_CMAC_C)

	#include "mbedtls/cmac.h"

	#include <string.h>

	#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
	#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 && MBEDTLS_AES_C */

	/* Implementation that should never be optimized out by the compiler */
	static void mbedtls_zeroize( void *v, size_t n ) {
	volatile unsigned char p = v; while( n-- ) p++ = 0;
	}

	/*
	* Initialize context
	*/
	void mbedtls_cmac_init( mbedtls_cmac_context *ctx )
	{
	memset( ctx, 0, sizeof( mbedtls_cmac_context ) );
	}


	/*
	* Multiplication by u in the Galois field of GF(2^n)
	*
	* As explained in the paper, this can computed:
	* If MSB(p) = 0, then p = (p << 1)
	* If MSB(p) = 1, then p = (p << 1) ^ R_n
	* with R_64 = 0x1B and R_128 = 0x87
	*
	* Input and output MUST not point to the same buffer
	* Block size must be 8 byes or 16 bytes.
	*/
	static int cmac_multiply_by_u( unsigned char *output,
	const unsigned char *input,
	size_t blocksize )
	{

	const unsigned char R_128 = 0x87;
	const unsigned char R_64 = 0x1B;
	unsigned char R_n, mask;
	unsigned char overflow = 0x00;
	int i, starting_index;

	starting_index = blocksize -1;

	if( blocksize == 16 ){
	R_n = R_128;
	} else if( blocksize == 8 ) {
	R_n = R_64;
	} else {
	return( MBEDTLS_ERR_CMAC_BAD_INPUT );
	}


	for( i = starting_index; i >= 0; i-- )
	{
	output[i] = input[i] << 1 \| overflow;
	overflow = input[i] >> 7;
	}

	/* mask = ( input[0] >> 7 ) ? 0xff : 0x00
	* using bit operations to avoid branches */
	/* MSVC has a warning about unary minus on unsigned, but this is
	* well-defined and precisely what we want to do here */
	#if defined(_MSC_VER)
	#pragma warning( push )
	#pragma warning( disable : 4146 )
	#endif
	mask = - ( input[0] >> 7 );
	#if defined(_MSC_VER)
	#pragma warning( pop )
	#endif

	output[starting_index] ^= R_n & mask;
	return( 0 );
	}

	/*
	* Generate subkeys
	*/
	static int cmac_generate_subkeys( mbedtls_cmac_context *ctx )
	{
	int ret, keybytes;
	unsigned char *L;
	size_t olen, block_size;

	ret = 0;
	block_size = ctx->cipher_ctx.cipher_info->block_size;

	L = mbedtls_calloc( block_size, sizeof( unsigned char ) );

	/* Calculate Ek(0) */
	memset( L, 0, block_size );
	if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx,
	L, block_size, L, &olen ) ) != 0 )
	{
	goto exit;
	}

	/*
	* Generate K1 and K2
	*/
	if( ( ret = cmac_multiply_by_u( ctx->K1, L , block_size ) ) != 0 )
	goto exit;
	if( ( cmac_multiply_by_u( ctx->K2, ctx->K1 , block_size ) ) != 0 )
	goto exit;

	exit:
	mbedtls_zeroize( L, sizeof( L ) );
	free( L );
	return( ret );
	}

	/*
	* Set key and prepare context for use
	*/
	int mbedtls_cmac_setkey( mbedtls_cmac_context *ctx,
	mbedtls_cipher_id_t cipher,
	const unsigned char *key,
	unsigned int keybits )
	{
	int ret, blocksize;
	const mbedtls_cipher_info_t *cipher_info;

	cipher_info = mbedtls_cipher_info_from_values( cipher, keybits,
	MBEDTLS_MODE_ECB );
	if( cipher_info == NULL )
	return( MBEDTLS_ERR_CMAC_BAD_INPUT );

	ctx->K1 = mbedtls_calloc( cipher_info->block_size, sizeof( unsigned char ) );
	ctx->K2 = mbedtls_calloc( cipher_info->block_size, sizeof( unsigned char ) );

	mbedtls_cipher_free( &ctx->cipher_ctx );

	if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
	return( ret );

	if( ( ret = mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits,
	MBEDTLS_ENCRYPT ) ) != 0 )
	{
	return( ret );
	}

	return( cmac_generate_subkeys( ctx ) );
	}

	/*
	* Free context
	*/
	void mbedtls_cmac_free( mbedtls_cmac_context *ctx )
	{
	int block_size;
	block_size = ctx->cipher_ctx.cipher_info->block_size;

	mbedtls_cipher_free( &ctx->cipher_ctx );

	mbedtls_zeroize( ctx->K1, block_size * sizeof( unsigned char ) );
	mbedtls_zeroize( ctx->K2, block_size * sizeof( unsigned char ) );
	mbedtls_free( ctx->K1 );
	mbedtls_free( ctx->K2 );
	}

	/*
	* Create padded last block from (partial) last block.
	*
	* We can't use the padding option from the cipher layer, as it only works for
	* CBC and we use ECB mode, and anyway we need to XOR K1 or K2 in addition.
	*/
	static void cmac_pad( unsigned char padded_block[16],
	size_t padded_block_len,
	const unsigned char *last_block,
	size_t last_block_len )
	{
	size_t j;

	for( j = 0; j < padded_block_len; j++ )
	{
	if( j < last_block_len )
	padded_block[j] = last_block[j];
	else if( j == last_block_len )
	padded_block[j] = 0x80;
	else
	padded_block[j] = 0x00;
	}
	}

	/*
	* XOR Block
	* Here, macro results in smaller compiled code than static inline function
	*/
	#define XOR_BLOCK( o, i1, i2 ) \
	for( i = 0; i < block_size; i++ ) \
	( o )[i] = ( i1 )[i] ^ ( i2 )[i];

	/*
	* Update the CMAC state using an input block x
	*/
	#define UPDATE_CMAC( x ) \
	do { \
	XOR_BLOCK( state, ( x ), state ); \
	if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, \
	state, block_size, \
	state, &olen ) ) != 0 ) \
	return( ret ); \
	} while( 0 )

	/*
	* Generate tag on complete message
	*/
	int mbedtls_cmac_generate( mbedtls_cmac_context *ctx,
	const unsigned char *input, size_t in_len,
	unsigned char *tag, size_t tag_len )

	{

	unsigned char *state;
	unsigned char *M_last;
	int n, i, j, ret, needs_padding;
	size_t olen, block_size;


	ret = 0;
	block_size = ctx->cipher_ctx.cipher_info->block_size;

	state = mbedtls_calloc( block_size, sizeof( unsigned char ) );
	M_last = mbedtls_calloc( block_size, sizeof( unsigned char ) );

	/*
	* Check in_len requirements: SP800-38B A
	* 4 is a worst case bottom limit
	*/
	if( tag_len < 4 \|\| tag_len > block_size \|\| tag_len % 2 != 0 )
	return( MBEDTLS_ERR_CMAC_BAD_INPUT );

	if( in_len == 0 )
	needs_padding = 1;
	else
	needs_padding = in_len % block_size != 0;

	n = in_len / block_size + needs_padding;

	/* Calculate last block */
	if( needs_padding )
	{
	cmac_pad( M_last, block_size, input + block_size * ( n - 1 ), in_len % block_size );
	XOR_BLOCK( M_last, M_last, ctx->K2 );
	}
	else
	{
	/* Last block is complete block */
	XOR_BLOCK( M_last, input + block_size * ( n - 1 ), ctx->K1 );
	}

	memset( state, 0, block_size );

	for( j = 0; j < n - 1; j++ )
	UPDATE_CMAC( input + block_size * j );

	UPDATE_CMAC( M_last );

	memcpy( tag, state, tag_len );

	exit:
	free( state );
	free( M_last );
	return( ret );
	}

	#undef XOR_BLOCK
	#undef UPDATE_CMAC

	/*
	* Verify tag on complete message
	*/
	int mbedtls_cmac_verify( mbedtls_cmac_context *ctx,
	const unsigned char *input, size_t in_len,
	const unsigned char *tag, size_t tag_len )
	{
	int ret;
	unsigned char *check_tag;
	unsigned char i;
	int diff;

	check_tag = mbedtls_calloc( ctx->cipher_ctx.cipher_info->block_size,
	sizeof( unsigned char ) );

	if( ( ret = mbedtls_cmac_generate( ctx, input, in_len,
	check_tag, tag_len ) ) != 0 )
	{
	goto exit;
	}

	/* Check tag in "constant-time" */
	for( diff = 0, i = 0; i < tag_len; i++ )
	diff \|= tag[i] ^ check_tag[i];

	if( diff != 0 )
	ret = MBEDTLS_ERR_CMAC_VERIFY_FAILED;
	goto exit;

	exit:
	free( check_tag );
	return( ret );
	}

	#ifdef MBEDTLS_AES_C
	/*
	* PRF based on CMAC with AES-128
	* See RFC 4615
	*/
	int mbedtls_aes_cmac_prf_128( const unsigned char *key, size_t key_length,
	const unsigned char *input, size_t in_len,
	unsigned char tag[16] )
	{
	int ret;
	mbedtls_cmac_context ctx;
	unsigned char zero_key[16];
	unsigned char int_key[16];

	mbedtls_cmac_init(&ctx );

	if( key_length == 16 )
	{
	/* Use key as is */
	memcpy( int_key, key, 16 );
	}
	else
	{
	mbedtls_cmac_context zero_ctx;

	/* Key is AES_CMAC( 0, key ) */
	mbedtls_cmac_init( &zero_ctx );
	memset( zero_key, 0, 16 );
	ret = mbedtls_cmac_setkey( &zero_ctx, MBEDTLS_CIPHER_ID_AES,
	zero_key, 8 * sizeof zero_key );
	if( ret != 0 )
	goto exit;

	ret = mbedtls_cmac_generate( &zero_ctx, key, key_length, int_key, 16 );
	if( ret != 0 )
	goto exit;
	}

	ret = mbedtls_cmac_setkey( &ctx, MBEDTLS_CIPHER_ID_AES,
	int_key, 8 * sizeof int_key );
	if( ret != 0 )
	goto exit;

	mbedtls_zeroize( int_key, sizeof( int_key ) );

	ret = mbedtls_cmac_generate( &ctx, input, in_len, tag, 16 );

	exit:
	mbedtls_cmac_free( &ctx );
	return( ret );
	}
	#endif /* MBEDTLS_AES_C */

	#ifdef MBEDTLS_SELF_TEST
	/*
	* CMAC test data from SP800-38B Appendix D.1 (corrected)
	* http://csrc.nist.gov/publications/nistpubs/800-38B/Updated_CMAC_Examples.pdf
	*
	* AES-CMAC-PRF-128 test data from RFC 4615
	* https://tools.ietf.org/html/rfc4615#page-4
	*/

	#define NB_CMAC_TESTS_PER_KEY 4
	#define NB_PRF_TESTS 3
	#define AES_BLOCK_SIZE 16
	#define DES3_BLOCK_SIZE 8

	#if defined(MBEDTLS_AES_C) \|\| defined(MBEDTLS_DES_C)
	/* All CMAC test inputs are truncated from the same 64 byte buffer. */
	static const unsigned char test_message[] = {
	0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
	0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
	0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
	0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
	0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
	0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
	0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
	0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10
	};
	#endif /* defined(MBEDTLS_AES_C) \|\| defined(MBEDTLS_DES_C) */

	#ifdef MBEDTLS_AES_C
	/* Truncation point of message for AES CMAC tests */
	static const size_t aes_message_lengths[NB_CMAC_TESTS_PER_KEY] = {
	0,
	16,
	40,
	64
	};

	/* AES 128 CMAC Test Data */
	static const unsigned char aes_128_key[] = {
	0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
	0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c
	};
	static const unsigned char aes_128_subkeys[2][AES_BLOCK_SIZE] = {
	{
	0xfb, 0xee, 0xd6, 0x18, 0x35, 0x71, 0x33, 0x66,
	0x7c, 0x85, 0xe0, 0x8f, 0x72, 0x36, 0xa8, 0xde
	},
	{
	0xf7, 0xdd, 0xac, 0x30, 0x6a, 0xe2, 0x66, 0xcc,
	0xf9, 0x0b, 0xc1, 0x1e, 0xe4, 0x6d, 0x51, 0x3b
	}
	};
	static const unsigned char aes_128_expected_result[NB_CMAC_TESTS_PER_KEY][AES_BLOCK_SIZE] = {
	{
	0xbb, 0x1d, 0x69, 0x29, 0xe9, 0x59, 0x37, 0x28,
	0x7f, 0xa3, 0x7d, 0x12, 0x9b, 0x75, 0x67, 0x46
	},
	{
	0x07, 0x0a, 0x16, 0xb4, 0x6b, 0x4d, 0x41, 0x44,
	0xf7, 0x9b, 0xdd, 0x9d, 0xd0, 0x4a, 0x28, 0x7c
	},
	{
	0xdf, 0xa6, 0x67, 0x47, 0xde, 0x9a, 0xe6, 0x30,
	0x30, 0xca, 0x32, 0x61, 0x14, 0x97, 0xc8, 0x27
	},
	{
	0x51, 0xf0, 0xbe, 0xbf, 0x7e, 0x3b, 0x9d, 0x92,
	0xfc, 0x49, 0x74, 0x17, 0x79, 0x36, 0x3c, 0xfe
	}
	};

	/* AES 192 CMAC Test Data */
	static const unsigned char aes_192_key[] = {
	0x8e, 0x73, 0xb0, 0xf7, 0xda, 0x0e, 0x64, 0x52,
	0xc8, 0x10, 0xf3, 0x2b, 0x80, 0x90, 0x79, 0xe5,
	0x62, 0xf8, 0xea, 0xd2, 0x52, 0x2c, 0x6b, 0x7b
	};
	static const unsigned char aes_192_subkeys[2][AES_BLOCK_SIZE] = {
	{
	0x44, 0x8a, 0x5b, 0x1c, 0x93, 0x51, 0x4b, 0x27,
	0x3e, 0xe6, 0x43, 0x9d, 0xd4, 0xda, 0xa2, 0x96
	},
	{
	0x89, 0x14, 0xb6, 0x39, 0x26, 0xa2, 0x96, 0x4e,
	0x7d, 0xcc, 0x87, 0x3b, 0xa9, 0xb5, 0x45, 0x2c
	}
	};
	static const unsigned char aes_192_expected_result[NB_CMAC_TESTS_PER_KEY][AES_BLOCK_SIZE] = {
	{
	0xd1, 0x7d, 0xdf, 0x46, 0xad, 0xaa, 0xcd, 0xe5,
	0x31, 0xca, 0xc4, 0x83, 0xde, 0x7a, 0x93, 0x67
	},
	{
	0x9e, 0x99, 0xa7, 0xbf, 0x31, 0xe7, 0x10, 0x90,
	0x06, 0x62, 0xf6, 0x5e, 0x61, 0x7c, 0x51, 0x84
	},
	{
	0x8a, 0x1d, 0xe5, 0xbe, 0x2e, 0xb3, 0x1a, 0xad,
	0x08, 0x9a, 0x82, 0xe6, 0xee, 0x90, 0x8b, 0x0e
	},
	{
	0xa1, 0xd5, 0xdf, 0x0e, 0xed, 0x79, 0x0f, 0x79,
	0x4d, 0x77, 0x58, 0x96, 0x59, 0xf3, 0x9a, 0x11
	}
	};

	/* AES 256 CMAC Test Data */
	static const unsigned char aes_256_key[] = {
	0x60, 0x3d, 0xeb, 0x10, 0x15, 0xca, 0x71, 0xbe,
	0x2b, 0x73, 0xae, 0xf0, 0x85, 0x7d, 0x77, 0x81,
	0x1f, 0x35, 0x2c, 0x07, 0x3b, 0x61, 0x08, 0xd7,
	0x2d, 0x98, 0x10, 0xa3, 0x09, 0x14, 0xdf, 0xf4
	};
	static const unsigned char aes_256_subkeys[2][AES_BLOCK_SIZE] = {
	{
	0xca, 0xd1, 0xed, 0x03, 0x29, 0x9e, 0xed, 0xac,
	0x2e, 0x9a, 0x99, 0x80, 0x86, 0x21, 0x50, 0x2f
	},
	{
	0x95, 0xa3, 0xda, 0x06, 0x53, 0x3d, 0xdb, 0x58,
	0x5d, 0x35, 0x33, 0x01, 0x0c, 0x42, 0xa0, 0xd9
	}
	};
	static const unsigned char aes_256_expected_result[NB_CMAC_TESTS_PER_KEY][AES_BLOCK_SIZE] = {
	{
	0x02, 0x89, 0x62, 0xf6, 0x1b, 0x7b, 0xf8, 0x9e,
	0xfc, 0x6b, 0x55, 0x1f, 0x46, 0x67, 0xd9, 0x83
	},
	{
	0x28, 0xa7, 0x02, 0x3f, 0x45, 0x2e, 0x8f, 0x82,
	0xbd, 0x4b, 0xf2, 0x8d, 0x8c, 0x37, 0xc3, 0x5c
	},
	{
	0xaa, 0xf3, 0xd8, 0xf1, 0xde, 0x56, 0x40, 0xc2,
	0x32, 0xf5, 0xb1, 0x69, 0xb9, 0xc9, 0x11, 0xe6
	},
	{
	0xe1, 0x99, 0x21, 0x90, 0x54, 0x9f, 0x6e, 0xd5,
	0x69, 0x6a, 0x2c, 0x05, 0x6c, 0x31, 0x54, 0x10
	}
	};
	#endif /* MBEDTLS_AES_C */

	#ifdef MBEDTLS_DES_C
	/* Truncation point of message for 3DES CMAC tests */
	static const size_t des3_message_lengths[NB_CMAC_TESTS_PER_KEY] = {
	0,
	8,
	20,
	32
	};

	/* 3DES 2 Key CMAC Test Data */
	static const unsigned char des3_2key_key[] = {
	0x4c, 0xf1, 0x51, 0x34, 0xa2, 0x85, 0x0d, 0xd5,
	0x8a, 0x3d, 0x10, 0xba, 0x80, 0x57, 0x0d, 0x38,
	0x4c, 0xf1, 0x51, 0x34, 0xa2, 0x85, 0x0d, 0xd5
	};
	static const unsigned char des3_2key_subkeys[2][8] = {
	{
	0x8e, 0xcf, 0x37, 0x3e, 0xd7, 0x1a, 0xfa, 0xef
	},
	{
	0x1d, 0x9e, 0x6e, 0x7d, 0xae, 0x35, 0xf5, 0xc5
	}
	};
	static const unsigned char T_3des_2key[NB_CMAC_TESTS_PER_KEY][DES3_BLOCK_SIZE] = {
	{
	0xbd, 0x2e, 0xbf, 0x9a, 0x3b, 0xa0, 0x03, 0x61
	},
	{
	0x4f, 0xf2, 0xab, 0x81, 0x3c, 0x53, 0xce, 0x83
	},
	{
	0x62, 0xdd, 0x1b, 0x47, 0x19, 0x02, 0xbd, 0x4e
	},
	{
	0x31, 0xb1, 0xe4, 0x31, 0xda, 0xbc, 0x4e, 0xb8
	}
	};

	/* 3DES 3 Key CMAC Test Data */
	static const unsigned char des3_3key_key[] = {
	0x8a, 0xa8, 0x3b, 0xf8, 0xcb, 0xda, 0x10, 0x62,
	0x0b, 0xc1, 0xbf, 0x19, 0xfb, 0xb6, 0xcd, 0x58,
	0xbc, 0x31, 0x3d, 0x4a, 0x37, 0x1c, 0xa8, 0xb5
	};
	static const unsigned char des3_3key_subkeys[2][8] = {
	{
	0x91, 0x98, 0xe9, 0xd3, 0x14, 0xe6, 0x53, 0x5f
	},
	{
	0x23, 0x31, 0xd3, 0xa6, 0x29, 0xcc, 0xa6, 0xa5
	}
	};
	static const unsigned char T_3des_3key[NB_CMAC_TESTS_PER_KEY][DES3_BLOCK_SIZE] = {
	{
	0xb7, 0xa6, 0x88, 0xe1, 0x22, 0xff, 0xaf, 0x95
	},
	{
	0x8e, 0x8f, 0x29, 0x31, 0x36, 0x28, 0x37, 0x97
	},
	{
	0x74, 0x3d, 0xdb, 0xe0, 0xce, 0x2d, 0xc2, 0xed
	},
	{
	0x33, 0xe6, 0xb1, 0x09, 0x24, 0x00, 0xea, 0xe5
	}
	};

	#endif /* MBEDTLS_DES_C */

	#ifdef MBEDTLS_AES_C
	/* AES AES-CMAC-PRF-128 Test Data */
	static const unsigned char PRFK[] = {
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
	0xed, 0xcb
	};

	/* Sizes in bytes */
	static const size_t PRFKlen[NB_PRF_TESTS] = {
	18,
	16,
	10
	};

	/* PRF M */
	static const unsigned char PRFM[] = {
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
	0x10, 0x11, 0x12, 0x13
	};

	static const unsigned char PRFT[NB_PRF_TESTS][16] = {
	{
	0x84, 0xa3, 0x48, 0xa4, 0xa4, 0x5d, 0x23, 0x5b,
	0xab, 0xff, 0xfc, 0x0d, 0x2b, 0x4d, 0xa0, 0x9a
	},
	{
	0x98, 0x0a, 0xe8, 0x7b, 0x5f, 0x4c, 0x9c, 0x52,
	0x14, 0xf5, 0xb6, 0xa8, 0x45, 0x5e, 0x4c, 0x2d
	},
	{
	0x29, 0x0d, 0x9e, 0x11, 0x2e, 0xdb, 0x09, 0xee,
	0x14, 0x1f, 0xcf, 0x64, 0xc0, 0xb7, 0x2f, 0x3d
	}
	};
	#endif /* MBEDTLS_AES_C */

	int test_cmac_with_cipher( int verbose,
	const unsigned char* testname,
	const unsigned char* key,
	int keybits,
	const unsigned char* messages,
	size_t message_lengths[4],
	const unsigned char* subkeys,
	const unsigned char* expected_result,
	mbedtls_cipher_id_t cipher_id,
	int block_size )
	{
	const int num_tests = 4;
	mbedtls_cmac_context ctx;
	int i, ret;
	unsigned char* tag;

	tag = mbedtls_calloc( block_size, sizeof( unsigned char ) );
	mbedtls_cmac_init( &ctx );

	if( ( ret = mbedtls_cmac_setkey( &ctx, cipher_id, key, keybits ) ) != 0 )
	{
	if( verbose != 0 )
	mbedtls_printf( " CMAC: setup failed\n" );
	goto exit;
	}

	if( ( ret = memcmp( ctx.K1, subkeys, block_size ) != 0 ) \|\|
	( ret = memcmp( ctx.K2, &subkeys[block_size], block_size ) != 0 ) )
	{
	if( verbose != 0 )
	mbedtls_printf( " CMAC: subkey generation failed\n" );
	goto exit;
	}

	for( i = 0; i < num_tests; i++ )
	{
	if( verbose != 0 )
	mbedtls_printf( " %s CMAC #%u: ", testname, i +1 );

	if( ( ret = mbedtls_cmac_generate( &ctx, messages, message_lengths[i], tag, block_size ) ) != 0 )
	{
	if( verbose != 0 )
	mbedtls_printf( "failed\n" );
	goto exit;
	}
	if( ( ret = memcmp( tag, &expected_result[i * block_size], block_size ) ) != 0 )
	{
	if( verbose != 0 )
	mbedtls_printf( "failed\n" );
	goto exit;
	}

	if( ( ret = mbedtls_cmac_verify( &ctx, messages, message_lengths[i], &expected_result[i * block_size], block_size ) != 0 ) )
	{
	if( verbose != 0 )
	mbedtls_printf( "failed\n" );
	goto exit;
	}
	mbedtls_printf( "passed\n" );
	}
	exit:
	free( tag );
	mbedtls_cmac_free( &ctx );
	return( ret );
	}

	#ifdef MBEDTLS_AES_C
	int test_aes128_cmac_prf( verbose ) {
	int i;
	int ret;
	unsigned char tag[16];
	for( i = 0; i < NB_PRF_TESTS; i++ )
	{
	mbedtls_printf( " AES CMAC 128 PRF #%u: ", i );
	ret = mbedtls_aes_cmac_prf_128( PRFK, PRFKlen[i], PRFM, 20, tag );
	if( ret != 0 \|\|
	memcmp( tag, PRFT[i], 16 ) != 0 )
	{
	if( verbose != 0 )
	mbedtls_printf( "failed\n" );

	return( ret );
	} else if( verbose != 0 )
	{
	mbedtls_printf( "passed\n" );
	}
	}
	return( ret );
	}
	#endif /* MBEDTLS_AES_C */

	int mbedtls_cmac_self_test( int verbose )
	{
	int ret;

	#ifdef MBEDTLS_AES_C
	test_cmac_with_cipher( verbose,
	"AES 128",
	aes_128_key,
	128,
	test_message,
	aes_message_lengths,
	aes_128_subkeys,
	aes_128_expected_result,
	MBEDTLS_CIPHER_ID_AES,
	AES_BLOCK_SIZE );

	test_cmac_with_cipher( verbose,
	"AES 192",
	aes_192_key,
	192,
	test_message,
	aes_message_lengths,
	aes_192_subkeys,
	aes_192_expected_result,
	MBEDTLS_CIPHER_ID_AES,
	AES_BLOCK_SIZE );

	test_cmac_with_cipher ( verbose,
	"AES 256",
	aes_256_key,
	256,
	test_message,
	aes_message_lengths,
	aes_256_subkeys,
	aes_256_expected_result,
	MBEDTLS_CIPHER_ID_AES,
	AES_BLOCK_SIZE );
	#endif /* MBEDTLS_AES_C */

	#ifdef MBEDTLS_DES_C
	test_cmac_with_cipher( verbose,
	"3DES 2 key",
	des3_2key_key,
	192,
	test_message,
	des3_message_lengths,
	des3_2key_subkeys,
	T_3des_2key,
	MBEDTLS_CIPHER_ID_3DES,
	DES3_BLOCK_SIZE );

	test_cmac_with_cipher( verbose,
	"3DES 3 key",
	des3_3key_key,
	192,
	test_message,
	des3_message_lengths,
	des3_3key_subkeys,
	T_3des_3key,
	MBEDTLS_CIPHER_ID_3DES,
	DES3_BLOCK_SIZE );
	#endif /* MBEDTLS_DES_C */

	#ifdef MBEDTLS_AES_C
	test_aes128_cmac_prf( verbose );
	#endif /* MBEDTLS_AES_C */

	if( verbose != 0 )
	mbedtls_printf( "\n" );

	return( 0 );
	}

	#endif /* MBEDTLS_SELF_TEST */

	#endif /* MBEDTLS_CMAC_C */