1 /** 2 * \file cmac.h 3 * 4 * \brief This file contains CMAC definitions and functions. 5 * 6 * The Cipher-based Message Authentication Code (CMAC) Mode for 7 * Authentication is defined in <em>RFC-4493: The AES-CMAC Algorithm</em>. 8 */ 9 /* 10 * Copyright The Mbed TLS Contributors 11 * SPDX-License-Identifier: Apache-2.0 12 * 13 * Licensed under the Apache License, Version 2.0 (the "License"); you may 14 * not use this file except in compliance with the License. 15 * You may obtain a copy of the License at 16 * 17 * http://www.apache.org/licenses/LICENSE-2.0 18 * 19 * Unless required by applicable law or agreed to in writing, software 20 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 21 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 22 * See the License for the specific language governing permissions and 23 * limitations under the License. 24 */ 25 26 #ifndef MBEDTLS_CMAC_H 27 #define MBEDTLS_CMAC_H 28 #include "mbedtls/private_access.h" 29 30 #include "mbedtls/build_info.h" 31 32 #include "mbedtls/cipher.h" 33 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 38 #define MBEDTLS_AES_BLOCK_SIZE 16 39 #define MBEDTLS_DES3_BLOCK_SIZE 8 40 41 #if defined(MBEDTLS_AES_C) 42 #define MBEDTLS_CIPHER_BLKSIZE_MAX 16 /**< The longest block used by CMAC is that of AES. */ 43 #else 44 #define MBEDTLS_CIPHER_BLKSIZE_MAX 8 /**< The longest block used by CMAC is that of 3DES. */ 45 #endif 46 47 #if !defined(MBEDTLS_CMAC_ALT) 48 49 /** 50 * The CMAC context structure. 51 */ 52 struct mbedtls_cmac_context_t 53 { 54 /** The internal state of the CMAC algorithm. */ 55 unsigned char MBEDTLS_PRIVATE(state)[MBEDTLS_CIPHER_BLKSIZE_MAX]; 56 57 /** Unprocessed data - either data that was not block aligned and is still 58 * pending processing, or the final block. */ 59 unsigned char MBEDTLS_PRIVATE(unprocessed_block)[MBEDTLS_CIPHER_BLKSIZE_MAX]; 60 61 /** The length of data pending processing. */ 62 size_t MBEDTLS_PRIVATE(unprocessed_len); 63 }; 64 65 #else /* !MBEDTLS_CMAC_ALT */ 66 #include "cmac_alt.h" 67 #endif /* !MBEDTLS_CMAC_ALT */ 68 69 /** 70 * \brief This function starts a new CMAC computation 71 * by setting the CMAC key, and preparing to authenticate 72 * the input data. 73 * It must be called with an initialized cipher context. 74 * 75 * Once this function has completed, data can be supplied 76 * to the CMAC computation by calling 77 * mbedtls_cipher_cmac_update(). 78 * 79 * To start a CMAC computation using the same key as a previous 80 * CMAC computation, use mbedtls_cipher_cmac_finish(). 81 * 82 * \note When the CMAC implementation is supplied by an alternate 83 * implementation (through #MBEDTLS_CMAC_ALT), some ciphers 84 * may not be supported by that implementation, and thus 85 * return an error. Alternate implementations must support 86 * AES-128 and AES-256, and may support AES-192 and 3DES. 87 * 88 * \param ctx The cipher context used for the CMAC operation, initialized 89 * as one of the following types: MBEDTLS_CIPHER_AES_128_ECB, 90 * MBEDTLS_CIPHER_AES_192_ECB, MBEDTLS_CIPHER_AES_256_ECB, 91 * or MBEDTLS_CIPHER_DES_EDE3_ECB. 92 * \param key The CMAC key. 93 * \param keybits The length of the CMAC key in bits. 94 * Must be supported by the cipher. 95 * 96 * \return \c 0 on success. 97 * \return A cipher-specific error code on failure. 98 */ 99 int mbedtls_cipher_cmac_starts( mbedtls_cipher_context_t *ctx, 100 const unsigned char *key, size_t keybits ); 101 102 /** 103 * \brief This function feeds an input buffer into an ongoing CMAC 104 * computation. 105 * 106 * The CMAC computation must have previously been started 107 * by calling mbedtls_cipher_cmac_starts() or 108 * mbedtls_cipher_cmac_reset(). 109 * 110 * Call this function as many times as needed to input the 111 * data to be authenticated. 112 * Once all of the required data has been input, 113 * call mbedtls_cipher_cmac_finish() to obtain the result 114 * of the CMAC operation. 115 * 116 * \param ctx The cipher context used for the CMAC operation. 117 * \param input The buffer holding the input data. 118 * \param ilen The length of the input data. 119 * 120 * \return \c 0 on success. 121 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA 122 * if parameter verification fails. 123 */ 124 int mbedtls_cipher_cmac_update( mbedtls_cipher_context_t *ctx, 125 const unsigned char *input, size_t ilen ); 126 127 /** 128 * \brief This function finishes an ongoing CMAC operation, and 129 * writes the result to the output buffer. 130 * 131 * It should be followed either by 132 * mbedtls_cipher_cmac_reset(), which starts another CMAC 133 * operation with the same key, or mbedtls_cipher_free(), 134 * which clears the cipher context. 135 * 136 * \param ctx The cipher context used for the CMAC operation. 137 * \param output The output buffer for the CMAC checksum result. 138 * 139 * \return \c 0 on success. 140 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA 141 * if parameter verification fails. 142 */ 143 int mbedtls_cipher_cmac_finish( mbedtls_cipher_context_t *ctx, 144 unsigned char *output ); 145 146 /** 147 * \brief This function starts a new CMAC operation with the same 148 * key as the previous one. 149 * 150 * It should be called after finishing the previous CMAC 151 * operation with mbedtls_cipher_cmac_finish(). 152 * After calling this function, 153 * call mbedtls_cipher_cmac_update() to supply the new 154 * CMAC operation with data. 155 * 156 * \param ctx The cipher context used for the CMAC operation. 157 * 158 * \return \c 0 on success. 159 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA 160 * if parameter verification fails. 161 */ 162 int mbedtls_cipher_cmac_reset( mbedtls_cipher_context_t *ctx ); 163 164 /** 165 * \brief This function calculates the full generic CMAC 166 * on the input buffer with the provided key. 167 * 168 * The function allocates the context, performs the 169 * calculation, and frees the context. 170 * 171 * The CMAC result is calculated as 172 * output = generic CMAC(cmac key, input buffer). 173 * 174 * \note When the CMAC implementation is supplied by an alternate 175 * implementation (through #MBEDTLS_CMAC_ALT), some ciphers 176 * may not be supported by that implementation, and thus 177 * return an error. Alternate implementations must support 178 * AES-128 and AES-256, and may support AES-192 and 3DES. 179 * 180 * \param cipher_info The cipher information. 181 * \param key The CMAC key. 182 * \param keylen The length of the CMAC key in bits. 183 * \param input The buffer holding the input data. 184 * \param ilen The length of the input data. 185 * \param output The buffer for the generic CMAC result. 186 * 187 * \return \c 0 on success. 188 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA 189 * if parameter verification fails. 190 */ 191 int mbedtls_cipher_cmac( const mbedtls_cipher_info_t *cipher_info, 192 const unsigned char *key, size_t keylen, 193 const unsigned char *input, size_t ilen, 194 unsigned char *output ); 195 196 #if defined(MBEDTLS_AES_C) 197 /** 198 * \brief This function implements the AES-CMAC-PRF-128 pseudorandom 199 * function, as defined in 200 * <em>RFC-4615: The Advanced Encryption Standard-Cipher-based 201 * Message Authentication Code-Pseudo-Random Function-128 202 * (AES-CMAC-PRF-128) Algorithm for the Internet Key 203 * Exchange Protocol (IKE).</em> 204 * 205 * \param key The key to use. 206 * \param key_len The key length in Bytes. 207 * \param input The buffer holding the input data. 208 * \param in_len The length of the input data in Bytes. 209 * \param output The buffer holding the generated 16 Bytes of 210 * pseudorandom output. 211 * 212 * \return \c 0 on success. 213 */ 214 int mbedtls_aes_cmac_prf_128( const unsigned char *key, size_t key_len, 215 const unsigned char *input, size_t in_len, 216 unsigned char output[16] ); 217 #endif /* MBEDTLS_AES_C */ 218 219 #if defined(MBEDTLS_SELF_TEST) && ( defined(MBEDTLS_AES_C) || defined(MBEDTLS_DES_C) ) 220 /** 221 * \brief The CMAC checkup routine. 222 * 223 * \note In case the CMAC routines are provided by an alternative 224 * implementation (i.e. #MBEDTLS_CMAC_ALT is defined), the 225 * checkup routine will succeed even if the implementation does 226 * not support the less widely used AES-192 or 3DES primitives. 227 * The self-test requires at least AES-128 and AES-256 to be 228 * supported by the underlying implementation. 229 * 230 * \return \c 0 on success. 231 * \return \c 1 on failure. 232 */ 233 int mbedtls_cmac_self_test( int verbose ); 234 #endif /* MBEDTLS_SELF_TEST && ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */ 235 236 #ifdef __cplusplus 237 } 238 #endif 239 240 #endif /* MBEDTLS_CMAC_H */ 241
