/** * \file cipher.h * * \brief Generic cipher wrapper. * * \author Adriaan de Jong * * Copyright (C) 2006-2014, ARM Limited, All Rights Reserved * * This file is part of mbed TLS (https://tls.mbed.org) * * 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. */ #ifndef POLARSSL_CIPHER_H #define POLARSSL_CIPHER_H #if !defined(POLARSSL_CONFIG_FILE) #include "config.h" #else #include POLARSSL_CONFIG_FILE #endif #include #if defined(POLARSSL_GCM_C) || defined(POLARSSL_CCM_C) #define POLARSSL_CIPHER_MODE_AEAD #endif #if defined(POLARSSL_CIPHER_MODE_CBC) #define POLARSSL_CIPHER_MODE_WITH_PADDING #endif #if defined(POLARSSL_ARC4_C) #define POLARSSL_CIPHER_MODE_STREAM #endif #if defined(_MSC_VER) && !defined(inline) #define inline _inline #else #if defined(__ARMCC_VERSION) && !defined(inline) #define inline __inline #endif /* __ARMCC_VERSION */ #endif /*_MSC_VER */ #define POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE -0x6080 /**< The selected feature is not available. */ #define POLARSSL_ERR_CIPHER_BAD_INPUT_DATA -0x6100 /**< Bad input parameters to function. */ #define POLARSSL_ERR_CIPHER_ALLOC_FAILED -0x6180 /**< Failed to allocate memory. */ #define POLARSSL_ERR_CIPHER_INVALID_PADDING -0x6200 /**< Input data contains invalid padding and is rejected. */ #define POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED -0x6280 /**< Decryption of block requires a full block. */ #define POLARSSL_ERR_CIPHER_AUTH_FAILED -0x6300 /**< Authentication failed (for AEAD modes). */ #define POLARSSL_CIPHER_VARIABLE_IV_LEN 0x01 /**< Cipher accepts IVs of variable length */ #define POLARSSL_CIPHER_VARIABLE_KEY_LEN 0x02 /**< Cipher accepts keys of variable length */ #ifdef __cplusplus extern "C" { #endif typedef enum { POLARSSL_CIPHER_ID_NONE = 0, POLARSSL_CIPHER_ID_NULL, POLARSSL_CIPHER_ID_AES, POLARSSL_CIPHER_ID_DES, POLARSSL_CIPHER_ID_3DES, /* Unused! */ POLARSSL_CIPHER_ID_CAMELLIA, POLARSSL_CIPHER_ID_BLOWFISH, POLARSSL_CIPHER_ID_ARC4, } cipher_id_t; typedef enum { POLARSSL_CIPHER_NONE = 0, POLARSSL_CIPHER_NULL, POLARSSL_CIPHER_AES_128_ECB, POLARSSL_CIPHER_AES_192_ECB, POLARSSL_CIPHER_AES_256_ECB, POLARSSL_CIPHER_AES_128_CBC, POLARSSL_CIPHER_AES_192_CBC, POLARSSL_CIPHER_AES_256_CBC, POLARSSL_CIPHER_AES_128_CFB128, POLARSSL_CIPHER_AES_192_CFB128, POLARSSL_CIPHER_AES_256_CFB128, POLARSSL_CIPHER_AES_128_CTR, POLARSSL_CIPHER_AES_192_CTR, POLARSSL_CIPHER_AES_256_CTR, POLARSSL_CIPHER_AES_128_GCM, POLARSSL_CIPHER_AES_192_GCM, POLARSSL_CIPHER_AES_256_GCM, POLARSSL_CIPHER_CAMELLIA_128_ECB, POLARSSL_CIPHER_CAMELLIA_192_ECB, POLARSSL_CIPHER_CAMELLIA_256_ECB, POLARSSL_CIPHER_CAMELLIA_128_CBC, POLARSSL_CIPHER_CAMELLIA_192_CBC, POLARSSL_CIPHER_CAMELLIA_256_CBC, POLARSSL_CIPHER_CAMELLIA_128_CFB128, POLARSSL_CIPHER_CAMELLIA_192_CFB128, POLARSSL_CIPHER_CAMELLIA_256_CFB128, POLARSSL_CIPHER_CAMELLIA_128_CTR, POLARSSL_CIPHER_CAMELLIA_192_CTR, POLARSSL_CIPHER_CAMELLIA_256_CTR, POLARSSL_CIPHER_CAMELLIA_128_GCM, POLARSSL_CIPHER_CAMELLIA_192_GCM, POLARSSL_CIPHER_CAMELLIA_256_GCM, POLARSSL_CIPHER_DES_ECB, POLARSSL_CIPHER_DES_CBC, POLARSSL_CIPHER_DES_EDE_ECB, POLARSSL_CIPHER_DES_EDE_CBC, POLARSSL_CIPHER_DES_EDE3_ECB, POLARSSL_CIPHER_DES_EDE3_CBC, POLARSSL_CIPHER_BLOWFISH_ECB, POLARSSL_CIPHER_BLOWFISH_CBC, POLARSSL_CIPHER_BLOWFISH_CFB64, POLARSSL_CIPHER_BLOWFISH_CTR, POLARSSL_CIPHER_ARC4_128, POLARSSL_CIPHER_AES_128_CCM, POLARSSL_CIPHER_AES_192_CCM, POLARSSL_CIPHER_AES_256_CCM, POLARSSL_CIPHER_CAMELLIA_128_CCM, POLARSSL_CIPHER_CAMELLIA_192_CCM, POLARSSL_CIPHER_CAMELLIA_256_CCM, } cipher_type_t; typedef enum { POLARSSL_MODE_NONE = 0, POLARSSL_MODE_ECB, POLARSSL_MODE_CBC, POLARSSL_MODE_CFB, POLARSSL_MODE_OFB, /* Unused! */ POLARSSL_MODE_CTR, POLARSSL_MODE_GCM, POLARSSL_MODE_STREAM, POLARSSL_MODE_CCM, } cipher_mode_t; typedef enum { POLARSSL_PADDING_PKCS7 = 0, /**< PKCS7 padding (default) */ POLARSSL_PADDING_ONE_AND_ZEROS, /**< ISO/IEC 7816-4 padding */ POLARSSL_PADDING_ZEROS_AND_LEN, /**< ANSI X.923 padding */ POLARSSL_PADDING_ZEROS, /**< zero padding (not reversible!) */ POLARSSL_PADDING_NONE, /**< never pad (full blocks only) */ } cipher_padding_t; typedef enum { POLARSSL_OPERATION_NONE = -1, POLARSSL_DECRYPT = 0, POLARSSL_ENCRYPT, } operation_t; enum { /** Undefined key length */ POLARSSL_KEY_LENGTH_NONE = 0, /** Key length, in bits (including parity), for DES keys */ POLARSSL_KEY_LENGTH_DES = 64, /** Key length, in bits (including parity), for DES in two key EDE */ POLARSSL_KEY_LENGTH_DES_EDE = 128, /** Key length, in bits (including parity), for DES in three-key EDE */ POLARSSL_KEY_LENGTH_DES_EDE3 = 192, }; /** Maximum length of any IV, in bytes */ #define POLARSSL_MAX_IV_LENGTH 16 /** Maximum block size of any cipher, in bytes */ #define POLARSSL_MAX_BLOCK_LENGTH 16 /** * Base cipher information. The non-mode specific functions and values. */ typedef struct { /** Base Cipher type (e.g. POLARSSL_CIPHER_ID_AES) */ cipher_id_t cipher; /** Encrypt using ECB */ int (*ecb_func)( void *ctx, operation_t mode, const unsigned char *input, unsigned char *output ); #if defined(POLARSSL_CIPHER_MODE_CBC) /** Encrypt using CBC */ int (*cbc_func)( void *ctx, operation_t mode, size_t length, unsigned char *iv, const unsigned char *input, unsigned char *output ); #endif #if defined(POLARSSL_CIPHER_MODE_CFB) /** Encrypt using CFB (Full length) */ int (*cfb_func)( void *ctx, operation_t mode, size_t length, size_t *iv_off, unsigned char *iv, const unsigned char *input, unsigned char *output ); #endif #if defined(POLARSSL_CIPHER_MODE_CTR) /** Encrypt using CTR */ int (*ctr_func)( void *ctx, size_t length, size_t *nc_off, unsigned char *nonce_counter, unsigned char *stream_block, const unsigned char *input, unsigned char *output ); #endif #if defined(POLARSSL_CIPHER_MODE_STREAM) /** Encrypt using STREAM */ int (*stream_func)( void *ctx, size_t length, const unsigned char *input, unsigned char *output ); #endif /** Set key for encryption purposes */ int (*setkey_enc_func)( void *ctx, const unsigned char *key, unsigned int key_length ); /** Set key for decryption purposes */ int (*setkey_dec_func)( void *ctx, const unsigned char *key, unsigned int key_length); /** Allocate a new context */ void * (*ctx_alloc_func)( void ); /** Free the given context */ void (*ctx_free_func)( void *ctx ); } cipher_base_t; /** * Cipher information. Allows cipher functions to be called in a generic way. */ typedef struct { /** Full cipher identifier (e.g. POLARSSL_CIPHER_AES_256_CBC) */ cipher_type_t type; /** Cipher mode (e.g. POLARSSL_MODE_CBC) */ cipher_mode_t mode; /** Cipher key length, in bits (default length for variable sized ciphers) * (Includes parity bits for ciphers like DES) */ unsigned int key_length; /** Name of the cipher */ const char * name; /** IV/NONCE size, in bytes. * For cipher that accept many sizes: recommended size */ unsigned int iv_size; /** Flags for variable IV size, variable key size, etc. */ int flags; /** block size, in bytes */ unsigned int block_size; /** Base cipher information and functions */ const cipher_base_t *base; } cipher_info_t; /** * Generic cipher context. */ typedef struct { /** Information about the associated cipher */ const cipher_info_t *cipher_info; /** Key length to use */ int key_length; /** Operation that the context's key has been initialised for */ operation_t operation; #if defined(POLARSSL_CIPHER_MODE_WITH_PADDING) /** Padding functions to use, if relevant for cipher mode */ void (*add_padding)( unsigned char *output, size_t olen, size_t data_len ); int (*get_padding)( unsigned char *input, size_t ilen, size_t *data_len ); #endif /** Buffer for data that hasn't been encrypted yet */ unsigned char unprocessed_data[POLARSSL_MAX_BLOCK_LENGTH]; /** Number of bytes that still need processing */ size_t unprocessed_len; /** Current IV or NONCE_COUNTER for CTR-mode */ unsigned char iv[POLARSSL_MAX_IV_LENGTH]; /** IV size in bytes (for ciphers with variable-length IVs) */ size_t iv_size; /** Cipher-specific context */ void *cipher_ctx; } cipher_context_t; /** * \brief Returns the list of ciphers supported by the generic cipher module. * * \return a statically allocated array of ciphers, the last entry * is 0. */ const int *cipher_list( void ); /** * \brief Returns the cipher information structure associated * with the given cipher name. * * \param cipher_name Name of the cipher to search for. * * \return the cipher information structure associated with the * given cipher_name, or NULL if not found. */ const cipher_info_t *cipher_info_from_string( const char *cipher_name ); /** * \brief Returns the cipher information structure associated * with the given cipher type. * * \param cipher_type Type of the cipher to search for. * * \return the cipher information structure associated with the * given cipher_type, or NULL if not found. */ const cipher_info_t *cipher_info_from_type( const cipher_type_t cipher_type ); /** * \brief Returns the cipher information structure associated * with the given cipher id, key size and mode. * * \param cipher_id Id of the cipher to search for * (e.g. POLARSSL_CIPHER_ID_AES) * \param key_length Length of the key in bits * \param mode Cipher mode (e.g. POLARSSL_MODE_CBC) * * \return the cipher information structure associated with the * given cipher_type, or NULL if not found. */ const cipher_info_t *cipher_info_from_values( const cipher_id_t cipher_id, int key_length, const cipher_mode_t mode ); /** * \brief Initialize a cipher_context (as NONE) */ void cipher_init( cipher_context_t *ctx ); /** * \brief Free and clear the cipher-specific context of ctx. * Freeing ctx itself remains the responsibility of the * caller. */ void cipher_free( cipher_context_t *ctx ); /** * \brief Initialises and fills the cipher context structure with * the appropriate values. * * \note Currently also clears structure. In future versions you * will be required to call cipher_init() on the structure * first. * * \param ctx context to initialise. May not be NULL. * \param cipher_info cipher to use. * * \return 0 on success, * POLARSSL_ERR_CIPHER_BAD_INPUT_DATA on parameter failure, * POLARSSL_ERR_CIPHER_ALLOC_FAILED if allocation of the * cipher-specific context failed. */ int cipher_init_ctx( cipher_context_t *ctx, const cipher_info_t *cipher_info ); #if ! defined(POLARSSL_DEPRECATED_REMOVED) #if defined(POLARSSL_DEPRECATED_WARNING) #define DEPRECATED __attribute__((deprecated)) #else #define DEPRECATED #endif /** * \brief Free the cipher-specific context of ctx. Freeing ctx * itself remains the responsibility of the caller. * * \deprecated Use cipher_free() instead * * \param ctx Free the cipher-specific context * * \returns 0 */ int cipher_free_ctx( cipher_context_t *ctx ) DEPRECATED; #undef DEPRECATED #endif /* POLARSSL_DEPRECATED_REMOVED */ /** * \brief Returns the block size of the given cipher. * * \param ctx cipher's context. Must have been initialised. * * \return size of the cipher's blocks, or 0 if ctx has not been * initialised. */ static inline unsigned int cipher_get_block_size( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return 0; return ctx->cipher_info->block_size; } /** * \brief Returns the mode of operation for the cipher. * (e.g. POLARSSL_MODE_CBC) * * \param ctx cipher's context. Must have been initialised. * * \return mode of operation, or POLARSSL_MODE_NONE if ctx * has not been initialised. */ static inline cipher_mode_t cipher_get_cipher_mode( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return POLARSSL_MODE_NONE; return ctx->cipher_info->mode; } /** * \brief Returns the size of the cipher's IV/NONCE in bytes. * * \param ctx cipher's context. Must have been initialised. * * \return If IV has not been set yet: (recommended) IV size * (0 for ciphers not using IV/NONCE). * If IV has already been set: actual size. */ static inline int cipher_get_iv_size( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return 0; if( ctx->iv_size != 0 ) return (int) ctx->iv_size; return ctx->cipher_info->iv_size; } /** * \brief Returns the type of the given cipher. * * \param ctx cipher's context. Must have been initialised. * * \return type of the cipher, or POLARSSL_CIPHER_NONE if ctx has * not been initialised. */ static inline cipher_type_t cipher_get_type( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return POLARSSL_CIPHER_NONE; return ctx->cipher_info->type; } /** * \brief Returns the name of the given cipher, as a string. * * \param ctx cipher's context. Must have been initialised. * * \return name of the cipher, or NULL if ctx was not initialised. */ static inline const char *cipher_get_name( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return 0; return ctx->cipher_info->name; } /** * \brief Returns the key length of the cipher. * * \param ctx cipher's context. Must have been initialised. * * \return cipher's key length, in bits, or * POLARSSL_KEY_LENGTH_NONE if ctx has not been * initialised. */ static inline int cipher_get_key_size( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return POLARSSL_KEY_LENGTH_NONE; return ctx->cipher_info->key_length; } /** * \brief Returns the operation of the given cipher. * * \param ctx cipher's context. Must have been initialised. * * \return operation (POLARSSL_ENCRYPT or POLARSSL_DECRYPT), * or POLARSSL_OPERATION_NONE if ctx has not been * initialised. */ static inline operation_t cipher_get_operation( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return POLARSSL_OPERATION_NONE; return ctx->operation; } /** * \brief Set the key to use with the given context. * * \param ctx generic cipher context. May not be NULL. Must have been * initialised using cipher_context_from_type or * cipher_context_from_string. * \param key The key to use. * \param key_length key length to use, in bits. * \param operation Operation that the key will be used for, either * POLARSSL_ENCRYPT or POLARSSL_DECRYPT. * * \returns 0 on success, POLARSSL_ERR_CIPHER_BAD_INPUT_DATA if * parameter verification fails or a cipher specific * error code. */ int cipher_setkey( cipher_context_t *ctx, const unsigned char *key, int key_length, const operation_t operation ); #if defined(POLARSSL_CIPHER_MODE_WITH_PADDING) /** * \brief Set padding mode, for cipher modes that use padding. * (Default: PKCS7 padding.) * * \param ctx generic cipher context * \param mode padding mode * * \returns 0 on success, POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE * if selected padding mode is not supported, or * POLARSSL_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode * does not support padding. */ int cipher_set_padding_mode( cipher_context_t *ctx, cipher_padding_t mode ); #endif /* POLARSSL_CIPHER_MODE_WITH_PADDING */ /** * \brief Set the initialization vector (IV) or nonce * * \param ctx generic cipher context * \param iv IV to use (or NONCE_COUNTER for CTR-mode ciphers) * \param iv_len IV length for ciphers with variable-size IV; * discarded by ciphers with fixed-size IV. * * \returns 0 on success, or POLARSSL_ERR_CIPHER_BAD_INPUT_DATA * * \note Some ciphers don't use IVs nor NONCE. For these * ciphers, this function has no effect. */ int cipher_set_iv( cipher_context_t *ctx, const unsigned char *iv, size_t iv_len ); /** * \brief Finish preparation of the given context * * \param ctx generic cipher context * * \returns 0 on success, POLARSSL_ERR_CIPHER_BAD_INPUT_DATA * if parameter verification fails. */ int cipher_reset( cipher_context_t *ctx ); #if defined(POLARSSL_GCM_C) /** * \brief Add additional data (for AEAD ciphers). * Currently only supported with GCM. * Must be called exactly once, after cipher_reset(). * * \param ctx generic cipher context * \param ad Additional data to use. * \param ad_len Length of ad. * * \return 0 on success, or a specific error code. */ int cipher_update_ad( cipher_context_t *ctx, const unsigned char *ad, size_t ad_len ); #endif /* POLARSSL_GCM_C */ /** * \brief Generic cipher update function. Encrypts/decrypts * using the given cipher context. Writes as many block * size'd blocks of data as possible to output. Any data * that cannot be written immediately will either be added * to the next block, or flushed when cipher_final is * called. * Exception: for POLARSSL_MODE_ECB, expects single block * in size (e.g. 16 bytes for AES) * * \param ctx generic cipher context * \param input buffer holding the input data * \param ilen length of the input data * \param output buffer for the output data. Should be able to hold at * least ilen + block_size. Cannot be the same buffer as * input! * \param olen length of the output data, will be filled with the * actual number of bytes written. * * \returns 0 on success, POLARSSL_ERR_CIPHER_BAD_INPUT_DATA if * parameter verification fails, * POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE on an * unsupported mode for a cipher or a cipher specific * error code. * * \note If the underlying cipher is GCM, all calls to this * function, except the last one before cipher_finish(), * must have ilen a multiple of the block size. */ int cipher_update( cipher_context_t *ctx, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen ); /** * \brief Generic cipher finalisation function. If data still * needs to be flushed from an incomplete block, data * contained within it will be padded with the size of * the last block, and written to the output buffer. * * \param ctx Generic cipher context * \param output buffer to write data to. Needs block_size available. * \param olen length of the data written to the output buffer. * * \returns 0 on success, POLARSSL_ERR_CIPHER_BAD_INPUT_DATA if * parameter verification fails, * POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption * expected a full block but was not provided one, * POLARSSL_ERR_CIPHER_INVALID_PADDING on invalid padding * while decrypting or a cipher specific error code. */ int cipher_finish( cipher_context_t *ctx, unsigned char *output, size_t *olen ); #if defined(POLARSSL_GCM_C) /** * \brief Write tag for AEAD ciphers. * Currently only supported with GCM. * Must be called after cipher_finish(). * * \param ctx Generic cipher context * \param tag buffer to write the tag * \param tag_len Length of the tag to write * * \return 0 on success, or a specific error code. */ int cipher_write_tag( cipher_context_t *ctx, unsigned char *tag, size_t tag_len ); /** * \brief Check tag for AEAD ciphers. * Currently only supported with GCM. * Must be called after cipher_finish(). * * \param ctx Generic cipher context * \param tag Buffer holding the tag * \param tag_len Length of the tag to check * * \return 0 on success, or a specific error code. */ int cipher_check_tag( cipher_context_t *ctx, const unsigned char *tag, size_t tag_len ); #endif /* POLARSSL_GCM_C */ /** * \brief Generic all-in-one encryption/decryption * (for all ciphers except AEAD constructs). * * \param ctx generic cipher context * \param iv IV to use (or NONCE_COUNTER for CTR-mode ciphers) * \param iv_len IV length for ciphers with variable-size IV; * discarded by ciphers with fixed-size IV. * \param input buffer holding the input data * \param ilen length of the input data * \param output buffer for the output data. Should be able to hold at * least ilen + block_size. Cannot be the same buffer as * input! * \param olen length of the output data, will be filled with the * actual number of bytes written. * * \note Some ciphers don't use IVs nor NONCE. For these * ciphers, use iv = NULL and iv_len = 0. * * \returns 0 on success, or * POLARSSL_ERR_CIPHER_BAD_INPUT_DATA, or * POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption * expected a full block but was not provided one, or * POLARSSL_ERR_CIPHER_INVALID_PADDING on invalid padding * while decrypting, or * a cipher specific error code. */ int cipher_crypt( cipher_context_t *ctx, const unsigned char *iv, size_t iv_len, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen ); #if defined(POLARSSL_CIPHER_MODE_AEAD) /** * \brief Generic autenticated encryption (AEAD ciphers). * * \param ctx generic cipher context * \param iv IV to use (or NONCE_COUNTER for CTR-mode ciphers) * \param iv_len IV length for ciphers with variable-size IV; * discarded by ciphers with fixed-size IV. * \param ad Additional data to authenticate. * \param ad_len Length of ad. * \param input buffer holding the input data * \param ilen length of the input data * \param output buffer for the output data. * Should be able to hold at least ilen. * \param olen length of the output data, will be filled with the * actual number of bytes written. * \param tag buffer for the authentication tag * \param tag_len desired tag length * * \returns 0 on success, or * POLARSSL_ERR_CIPHER_BAD_INPUT_DATA, or * a cipher specific error code. */ int cipher_auth_encrypt( cipher_context_t *ctx, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen, unsigned char *tag, size_t tag_len ); /** * \brief Generic autenticated decryption (AEAD ciphers). * * \param ctx generic cipher context * \param iv IV to use (or NONCE_COUNTER for CTR-mode ciphers) * \param iv_len IV length for ciphers with variable-size IV; * discarded by ciphers with fixed-size IV. * \param ad Additional data to be authenticated. * \param ad_len Length of ad. * \param input buffer holding the input data * \param ilen length of the input data * \param output buffer for the output data. * Should be able to hold at least ilen. * \param olen length of the output data, will be filled with the * actual number of bytes written. * \param tag buffer holding the authentication tag * \param tag_len length of the authentication tag * * \returns 0 on success, or * POLARSSL_ERR_CIPHER_BAD_INPUT_DATA, or * POLARSSL_ERR_CIPHER_AUTH_FAILED if data isn't authentic, * or a cipher specific error code. * * \note If the data is not authentic, then the output buffer * is zeroed out to prevent the unauthentic plaintext to * be used by mistake, making this interface safer. */ int cipher_auth_decrypt( cipher_context_t *ctx, const unsigned char *iv, size_t iv_len, const unsigned char *ad, size_t ad_len, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen, const unsigned char *tag, size_t tag_len ); #endif /* POLARSSL_CIPHER_MODE_AEAD */ /** * \brief Checkup routine * * \return 0 if successful, or 1 if the test failed */ int cipher_self_test( int verbose ); #ifdef __cplusplus } #endif #endif /* POLARSSL_CIPHER_H */