/** * \file ccm.h * * \brief This file provides an API for the CCM authenticated encryption * mode for block ciphers. * * CCM combines Counter mode encryption with CBC-MAC authentication * for 128-bit block ciphers. * * Input to CCM includes the following elements: * * * Definition of CCM: * http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf * RFC 3610 "Counter with CBC-MAC (CCM)" * * Related: * RFC 5116 "An Interface and Algorithms for Authenticated Encryption" * * Definition of CCM*: * IEEE 802.15.4 - IEEE Standard for Local and metropolitan area networks * Integer representation is fixed most-significant-octet-first order and * the representation of octets is most-significant-bit-first order. This is * consistent with RFC 3610. */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef MBEDTLS_CCM_H #define MBEDTLS_CCM_H #include "mbedtls/private_access.h" #include "mbedtls/build_info.h" #include "mbedtls/cipher.h" #if defined(MBEDTLS_BLOCK_CIPHER_C) #include "mbedtls/block_cipher.h" #endif #define MBEDTLS_CCM_DECRYPT 0 #define MBEDTLS_CCM_ENCRYPT 1 #define MBEDTLS_CCM_STAR_DECRYPT 2 #define MBEDTLS_CCM_STAR_ENCRYPT 3 /** Bad input parameters to the function. */ #define MBEDTLS_ERR_CCM_BAD_INPUT -0x000D /** Authenticated decryption failed. */ #define MBEDTLS_ERR_CCM_AUTH_FAILED -0x000F #ifdef __cplusplus extern "C" { #endif #if !defined(MBEDTLS_CCM_ALT) // Regular implementation // /** * \brief The CCM context-type definition. The CCM context is passed * to the APIs called. */ typedef struct mbedtls_ccm_context { unsigned char MBEDTLS_PRIVATE(y)[16]; /*!< The Y working buffer */ unsigned char MBEDTLS_PRIVATE(ctr)[16]; /*!< The counter buffer */ size_t MBEDTLS_PRIVATE(plaintext_len); /*!< Total plaintext length */ size_t MBEDTLS_PRIVATE(add_len); /*!< Total authentication data length */ size_t MBEDTLS_PRIVATE(tag_len); /*!< Total tag length */ size_t MBEDTLS_PRIVATE(processed); /*!< Track how many bytes of input data were processed (chunked input). Used independently for both auth data and plaintext/ciphertext. This variable is set to zero after auth data input is finished. */ unsigned int MBEDTLS_PRIVATE(q); /*!< The Q working value */ unsigned int MBEDTLS_PRIVATE(mode); /*!< The operation to perform: #MBEDTLS_CCM_ENCRYPT or #MBEDTLS_CCM_DECRYPT or #MBEDTLS_CCM_STAR_ENCRYPT or #MBEDTLS_CCM_STAR_DECRYPT. */ #if defined(MBEDTLS_BLOCK_CIPHER_C) mbedtls_block_cipher_context_t MBEDTLS_PRIVATE(block_cipher_ctx); /*!< The cipher context used. */ #else mbedtls_cipher_context_t MBEDTLS_PRIVATE(cipher_ctx); /*!< The cipher context used. */ #endif int MBEDTLS_PRIVATE(state); /*!< Working value holding context's state. Used for chunked data input */ } mbedtls_ccm_context; #else /* MBEDTLS_CCM_ALT */ #include "ccm_alt.h" #endif /* MBEDTLS_CCM_ALT */ /** * \brief This function initializes the specified CCM context, * to make references valid, and prepare the context * for mbedtls_ccm_setkey() or mbedtls_ccm_free(). * * \param ctx The CCM context to initialize. This must not be \c NULL. */ void mbedtls_ccm_init(mbedtls_ccm_context *ctx); /** * \brief This function initializes the CCM context set in the * \p ctx parameter and sets the encryption key. * * \param ctx The CCM context to initialize. This must be an initialized * context. * \param cipher The 128-bit block cipher to use. * \param key The encryption key. This must not be \c NULL. * \param keybits The key size in bits. This must be acceptable by the cipher. * * \return \c 0 on success. * \return A CCM or cipher-specific error code on failure. */ int mbedtls_ccm_setkey(mbedtls_ccm_context *ctx, mbedtls_cipher_id_t cipher, const unsigned char *key, unsigned int keybits); /** * \brief This function releases and clears the specified CCM context * and underlying cipher sub-context. * * \param ctx The CCM context to clear. If this is \c NULL, the function * has no effect. Otherwise, this must be initialized. */ void mbedtls_ccm_free(mbedtls_ccm_context *ctx); /** * \brief This function encrypts a buffer using CCM. * * \note The tag is written to a separate buffer. To concatenate * the \p tag with the \p output, as done in RFC-3610: * Counter with CBC-MAC (CCM), use * \p tag = \p output + \p length, and make sure that the * output buffer is at least \p length + \p tag_len wide. * * \param ctx The CCM context to use for encryption. This must be * initialized and bound to a key. * \param length The length of the input data in Bytes. * \param iv The initialization vector (nonce). This must be a readable * buffer of at least \p iv_len Bytes. * \param iv_len The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, * or 13. The length L of the message length field is * 15 - \p iv_len. * \param ad The additional data field. If \p ad_len is greater than * zero, \p ad must be a readable buffer of at least that * length. * \param ad_len The length of additional data in Bytes. * This must be less than `2^16 - 2^8`. * \param input The buffer holding the input data. If \p length is greater * than zero, \p input must be a readable buffer of at least * that length. * \param output The buffer holding the output data. If \p length is greater * than zero, \p output must be a writable buffer of at least * that length. * \param tag The buffer holding the authentication field. This must be a * writable buffer of at least \p tag_len Bytes. * \param tag_len The length of the authentication field to generate in Bytes: * 4, 6, 8, 10, 12, 14 or 16. * * \return \c 0 on success. * \return A CCM or cipher-specific error code on failure. */ int mbedtls_ccm_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, const unsigned char *input, unsigned char *output, unsigned char *tag, size_t tag_len); /** * \brief This function encrypts a buffer using CCM*. * * \note The tag is written to a separate buffer. To concatenate * the \p tag with the \p output, as done in RFC-3610: * Counter with CBC-MAC (CCM), use * \p tag = \p output + \p length, and make sure that the * output buffer is at least \p length + \p tag_len wide. * * \note When using this function in a variable tag length context, * the tag length has to be encoded into the \p iv passed to * this function. * * \param ctx The CCM context to use for encryption. This must be * initialized and bound to a key. * \param length The length of the input data in Bytes. * For tag length = 0, input length is ignored. * \param iv The initialization vector (nonce). This must be a readable * buffer of at least \p iv_len Bytes. * \param iv_len The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, * or 13. The length L of the message length field is * 15 - \p iv_len. * \param ad The additional data field. This must be a readable buffer of * at least \p ad_len Bytes. * \param ad_len The length of additional data in Bytes. * This must be less than 2^16 - 2^8. * \param input The buffer holding the input data. If \p length is greater * than zero, \p input must be a readable buffer of at least * that length. * \param output The buffer holding the output data. If \p length is greater * than zero, \p output must be a writable buffer of at least * that length. * \param tag The buffer holding the authentication field. This must be a * writable buffer of at least \p tag_len Bytes. * \param tag_len The length of the authentication field to generate in Bytes: * 0, 4, 6, 8, 10, 12, 14 or 16. * * \warning Passing \c 0 as \p tag_len means that the message is no * longer authenticated. * * \return \c 0 on success. * \return A CCM or cipher-specific error code on failure. */ int mbedtls_ccm_star_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, const unsigned char *input, unsigned char *output, unsigned char *tag, size_t tag_len); /** * \brief This function performs a CCM authenticated decryption of a * buffer. * * \param ctx The CCM context to use for decryption. This must be * initialized and bound to a key. * \param length The length of the input data in Bytes. * \param iv The initialization vector (nonce). This must be a readable * buffer of at least \p iv_len Bytes. * \param iv_len The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, * or 13. The length L of the message length field is * 15 - \p iv_len. * \param ad The additional data field. This must be a readable buffer * of at least that \p ad_len Bytes.. * \param ad_len The length of additional data in Bytes. * This must be less than 2^16 - 2^8. * \param input The buffer holding the input data. If \p length is greater * than zero, \p input must be a readable buffer of at least * that length. * \param output The buffer holding the output data. If \p length is greater * than zero, \p output must be a writable buffer of at least * that length. * \param tag The buffer holding the authentication field. This must be a * readable buffer of at least \p tag_len Bytes. * \param tag_len The length of the authentication field to generate in Bytes: * 4, 6, 8, 10, 12, 14 or 16. * * \return \c 0 on success. This indicates that the message is authentic. * \return #MBEDTLS_ERR_CCM_AUTH_FAILED if the tag does not match. * \return A cipher-specific error code on calculation failure. */ int mbedtls_ccm_auth_decrypt(mbedtls_ccm_context *ctx, size_t length, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, const unsigned char *input, unsigned char *output, const unsigned char *tag, size_t tag_len); /** * \brief This function performs a CCM* authenticated decryption of a * buffer. * * \note When using this function in a variable tag length context, * the tag length has to be decoded from \p iv and passed to * this function as \p tag_len. (\p tag needs to be adjusted * accordingly.) * * \param ctx The CCM context to use for decryption. This must be * initialized and bound to a key. * \param length The length of the input data in Bytes. * For tag length = 0, input length is ignored. * \param iv The initialization vector (nonce). This must be a readable * buffer of at least \p iv_len Bytes. * \param iv_len The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, * or 13. The length L of the message length field is * 15 - \p iv_len. * \param ad The additional data field. This must be a readable buffer of * at least that \p ad_len Bytes. * \param ad_len The length of additional data in Bytes. * This must be less than 2^16 - 2^8. * \param input The buffer holding the input data. If \p length is greater * than zero, \p input must be a readable buffer of at least * that length. * \param output The buffer holding the output data. If \p length is greater * than zero, \p output must be a writable buffer of at least * that length. * \param tag The buffer holding the authentication field. This must be a * readable buffer of at least \p tag_len Bytes. * \param tag_len The length of the authentication field in Bytes. * 0, 4, 6, 8, 10, 12, 14 or 16. * * \warning Passing \c 0 as \p tag_len means that the message is nos * longer authenticated. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CCM_AUTH_FAILED if the tag does not match. * \return A cipher-specific error code on calculation failure. */ int mbedtls_ccm_star_auth_decrypt(mbedtls_ccm_context *ctx, size_t length, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, const unsigned char *input, unsigned char *output, const unsigned char *tag, size_t tag_len); /** * \brief This function starts a CCM encryption or decryption * operation. * * This function and mbedtls_ccm_set_lengths() must be called * before calling mbedtls_ccm_update_ad() or * mbedtls_ccm_update(). This function can be called before * or after mbedtls_ccm_set_lengths(). * * \note This function is not implemented in Mbed TLS yet. * * \param ctx The CCM context. This must be initialized. * \param mode The operation to perform: #MBEDTLS_CCM_ENCRYPT or * #MBEDTLS_CCM_DECRYPT or #MBEDTLS_CCM_STAR_ENCRYPT or * #MBEDTLS_CCM_STAR_DECRYPT. * \param iv The initialization vector. This must be a readable buffer * of at least \p iv_len Bytes. * \param iv_len The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, * or 13. The length L of the message length field is * 15 - \p iv_len. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CCM_BAD_INPUT on failure: * \p ctx is in an invalid state, * \p mode is invalid, * \p iv_len is invalid (lower than \c 7 or greater than * \c 13). */ int mbedtls_ccm_starts(mbedtls_ccm_context *ctx, int mode, const unsigned char *iv, size_t iv_len); /** * \brief This function declares the lengths of the message * and additional data for a CCM encryption or decryption * operation. * * This function and mbedtls_ccm_starts() must be called * before calling mbedtls_ccm_update_ad() or * mbedtls_ccm_update(). This function can be called before * or after mbedtls_ccm_starts(). * * \note This function is not implemented in Mbed TLS yet. * * \param ctx The CCM context. This must be initialized. * \param total_ad_len The total length of additional data in bytes. * This must be less than `2^16 - 2^8`. * \param plaintext_len The length in bytes of the plaintext to encrypt or * result of the decryption (thus not encompassing the * additional data that are not encrypted). * \param tag_len The length of the tag to generate in Bytes: * 4, 6, 8, 10, 12, 14 or 16. * For CCM*, zero is also valid. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CCM_BAD_INPUT on failure: * \p ctx is in an invalid state, * \p total_ad_len is greater than \c 0xFF00. */ int mbedtls_ccm_set_lengths(mbedtls_ccm_context *ctx, size_t total_ad_len, size_t plaintext_len, size_t tag_len); /** * \brief This function feeds an input buffer as associated data * (authenticated but not encrypted data) in a CCM * encryption or decryption operation. * * You may call this function zero, one or more times * to pass successive parts of the additional data. The * lengths \p ad_len of the data parts should eventually add * up exactly to the total length of additional data * \c total_ad_len passed to mbedtls_ccm_set_lengths(). You * may not call this function after calling * mbedtls_ccm_update(). * * \note This function is not implemented in Mbed TLS yet. * * \param ctx The CCM context. This must have been started with * mbedtls_ccm_starts(), the lengths of the message and * additional data must have been declared with * mbedtls_ccm_set_lengths() and this must not have yet * received any input with mbedtls_ccm_update(). * \param ad The buffer holding the additional data, or \c NULL * if \p ad_len is \c 0. * \param ad_len The length of the additional data. If \c 0, * \p ad may be \c NULL. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CCM_BAD_INPUT on failure: * \p ctx is in an invalid state, * total input length too long. */ int mbedtls_ccm_update_ad(mbedtls_ccm_context *ctx, const unsigned char *ad, size_t ad_len); /** * \brief This function feeds an input buffer into an ongoing CCM * encryption or decryption operation. * * You may call this function zero, one or more times * to pass successive parts of the input: the plaintext to * encrypt, or the ciphertext (not including the tag) to * decrypt. After the last part of the input, call * mbedtls_ccm_finish(). The lengths \p input_len of the * data parts should eventually add up exactly to the * plaintext length \c plaintext_len passed to * mbedtls_ccm_set_lengths(). * * This function may produce output in one of the following * ways: * - Immediate output: the output length is always equal * to the input length. * - Buffered output: except for the last part of input data, * the output consists of a whole number of 16-byte blocks. * If the total input length so far (not including * associated data) is 16 \* *B* + *A* with *A* < 16 then * the total output length is 16 \* *B*. * For the last part of input data, the output length is * equal to the input length plus the number of bytes (*A*) * buffered in the previous call to the function (if any). * The function uses the plaintext length * \c plaintext_len passed to mbedtls_ccm_set_lengths() * to detect the last part of input data. * * In particular: * - It is always correct to call this function with * \p output_size >= \p input_len + 15. * - If \p input_len is a multiple of 16 for all the calls * to this function during an operation (not necessary for * the last one) then it is correct to use \p output_size * =\p input_len. * * \note This function is not implemented in Mbed TLS yet. * * \param ctx The CCM context. This must have been started with * mbedtls_ccm_starts() and the lengths of the message and * additional data must have been declared with * mbedtls_ccm_set_lengths(). * \param input The buffer holding the input data. If \p input_len * is greater than zero, this must be a readable buffer * of at least \p input_len bytes. * \param input_len The length of the input data in bytes. * \param output The buffer for the output data. If \p output_size * is greater than zero, this must be a writable buffer of * at least \p output_size bytes. * \param output_size The size of the output buffer in bytes. * See the function description regarding the output size. * \param output_len On success, \p *output_len contains the actual * length of the output written in \p output. * On failure, the content of \p *output_len is * unspecified. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CCM_BAD_INPUT on failure: * \p ctx is in an invalid state, * total input length too long, * or \p output_size too small. */ int mbedtls_ccm_update(mbedtls_ccm_context *ctx, const unsigned char *input, size_t input_len, unsigned char *output, size_t output_size, size_t *output_len); /** * \brief This function finishes the CCM operation and generates * the authentication tag. * * It wraps up the CCM stream, and generates the * tag. The tag can have a maximum length of 16 Bytes. * * \note This function is not implemented in Mbed TLS yet. * * \param ctx The CCM context. This must have been started with * mbedtls_ccm_starts() and the lengths of the message and * additional data must have been declared with * mbedtls_ccm_set_lengths(). * \param tag The buffer for holding the tag. If \p tag_len is greater * than zero, this must be a writable buffer of at least \p * tag_len Bytes. * \param tag_len The length of the tag. Must match the tag length passed to * mbedtls_ccm_set_lengths() function. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CCM_BAD_INPUT on failure: * \p ctx is in an invalid state, * invalid value of \p tag_len, * the total amount of additional data passed to * mbedtls_ccm_update_ad() was lower than the total length of * additional data \c total_ad_len passed to * mbedtls_ccm_set_lengths(), * the total amount of input data passed to * mbedtls_ccm_update() was lower than the plaintext length * \c plaintext_len passed to mbedtls_ccm_set_lengths(). */ int mbedtls_ccm_finish(mbedtls_ccm_context *ctx, unsigned char *tag, size_t tag_len); #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_CCM_GCM_CAN_AES) /** * \brief The CCM checkup routine. * * \return \c 0 on success. * \return \c 1 on failure. */ int mbedtls_ccm_self_test(int verbose); #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */ #ifdef __cplusplus } #endif #endif /* MBEDTLS_CCM_H */