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Diff: include/mbedtls/hmac_drbg.h
- Revision:
- 0:cdf462088d13
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/include/mbedtls/hmac_drbg.h Thu Jan 05 00:18:44 2017 +0000 @@ -0,0 +1,299 @@ +/** + * \file hmac_drbg.h + * + * \brief HMAC_DRBG (NIST SP 800-90A) + * + * 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) + */ +#ifndef MBEDTLS_HMAC_DRBG_H +#define MBEDTLS_HMAC_DRBG_H + +#include "md.h" + +#if defined(MBEDTLS_THREADING_C) +#include "mbedtls/threading.h" +#endif + +/* + * Error codes + */ +#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */ +#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */ +#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */ +#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED -0x0009 /**< The entropy source failed. */ + +/** + * \name SECTION: Module settings + * + * The configuration options you can set for this module are in this section. + * Either change them in config.h or define them on the compiler command line. + * \{ + */ + +#if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL) +#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */ +#endif + +#if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT) +#define MBEDTLS_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */ +#endif + +#if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST) +#define MBEDTLS_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */ +#endif + +#if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT) +#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */ +#endif + +/* \} name SECTION: Module settings */ + +#define MBEDTLS_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */ +#define MBEDTLS_HMAC_DRBG_PR_ON 1 /**< Prediction resistance enabled */ + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * HMAC_DRBG context. + */ +typedef struct +{ + /* Working state: the key K is not stored explicitely, + * but is implied by the HMAC context */ + mbedtls_md_context_t md_ctx; /*!< HMAC context (inc. K) */ + unsigned char V[MBEDTLS_MD_MAX_SIZE]; /*!< V in the spec */ + int reseed_counter; /*!< reseed counter */ + + /* Administrative state */ + size_t entropy_len; /*!< entropy bytes grabbed on each (re)seed */ + int prediction_resistance; /*!< enable prediction resistance (Automatic + reseed before every random generation) */ + int reseed_interval; /*!< reseed interval */ + + /* Callbacks */ + int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */ + void *p_entropy; /*!< context for the entropy function */ + +#if defined(MBEDTLS_THREADING_C) + mbedtls_threading_mutex_t mutex; +#endif +} mbedtls_hmac_drbg_context; + +/** + * \brief HMAC_DRBG context initialization + * Makes the context ready for mbedtls_hmac_drbg_seed(), + * mbedtls_hmac_drbg_seed_buf() or + * mbedtls_hmac_drbg_free(). + * + * \param ctx HMAC_DRBG context to be initialized + */ +void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx ); + +/** + * \brief HMAC_DRBG initial seeding + * Seed and setup entropy source for future reseeds. + * + * \param ctx HMAC_DRBG context to be seeded + * \param md_info MD algorithm to use for HMAC_DRBG + * \param f_entropy Entropy callback (p_entropy, buffer to fill, buffer + * length) + * \param p_entropy Entropy context + * \param custom Personalization data (Device specific identifiers) + * (Can be NULL) + * \param len Length of personalization data + * + * \note The "security strength" as defined by NIST is set to: + * 128 bits if md_alg is SHA-1, + * 192 bits if md_alg is SHA-224, + * 256 bits if md_alg is SHA-256 or higher. + * Note that SHA-256 is just as efficient as SHA-224. + * + * \return 0 if successful, or + * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or + * MBEDTLS_ERR_MD_ALLOC_FAILED, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED. + */ +int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx, + const mbedtls_md_info_t * md_info, + int (*f_entropy)(void *, unsigned char *, size_t), + void *p_entropy, + const unsigned char *custom, + size_t len ); + +/** + * \brief Initilisation of simpified HMAC_DRBG (never reseeds). + * (For use with deterministic ECDSA.) + * + * \param ctx HMAC_DRBG context to be initialised + * \param md_info MD algorithm to use for HMAC_DRBG + * \param data Concatenation of entropy string and additional data + * \param data_len Length of data in bytes + * + * \return 0 if successful, or + * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or + * MBEDTLS_ERR_MD_ALLOC_FAILED. + */ +int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx, + const mbedtls_md_info_t * md_info, + const unsigned char *data, size_t data_len ); + +/** + * \brief Enable / disable prediction resistance (Default: Off) + * + * Note: If enabled, entropy is used for ctx->entropy_len before each call! + * Only use this if you have ample supply of good entropy! + * + * \param ctx HMAC_DRBG context + * \param resistance MBEDTLS_HMAC_DRBG_PR_ON or MBEDTLS_HMAC_DRBG_PR_OFF + */ +void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx, + int resistance ); + +/** + * \brief Set the amount of entropy grabbed on each reseed + * (Default: given by the security strength, which + * depends on the hash used, see \c mbedtls_hmac_drbg_init() ) + * + * \param ctx HMAC_DRBG context + * \param len Amount of entropy to grab, in bytes + */ +void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx, + size_t len ); + +/** + * \brief Set the reseed interval + * (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL) + * + * \param ctx HMAC_DRBG context + * \param interval Reseed interval + */ +void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx, + int interval ); + +/** + * \brief HMAC_DRBG update state + * + * \param ctx HMAC_DRBG context + * \param additional Additional data to update state with, or NULL + * \param add_len Length of additional data, or 0 + * + * \note Additional data is optional, pass NULL and 0 as second + * third argument if no additional data is being used. + */ +void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, size_t add_len ); + +/** + * \brief HMAC_DRBG reseeding (extracts data from entropy source) + * + * \param ctx HMAC_DRBG context + * \param additional Additional data to add to state (Can be NULL) + * \param len Length of additional data + * + * \return 0 if successful, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED + */ +int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, size_t len ); + +/** + * \brief HMAC_DRBG generate random with additional update input + * + * Note: Automatically reseeds if reseed_counter is reached or PR is enabled. + * + * \param p_rng HMAC_DRBG context + * \param output Buffer to fill + * \param output_len Length of the buffer + * \param additional Additional data to update with (can be NULL) + * \param add_len Length of additional data (can be 0) + * + * \return 0 if successful, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or + * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or + * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG. + */ +int mbedtls_hmac_drbg_random_with_add( void *p_rng, + unsigned char *output, size_t output_len, + const unsigned char *additional, + size_t add_len ); + +/** + * \brief HMAC_DRBG generate random + * + * Note: Automatically reseeds if reseed_counter is reached or PR is enabled. + * + * \param p_rng HMAC_DRBG context + * \param output Buffer to fill + * \param out_len Length of the buffer + * + * \return 0 if successful, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or + * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG + */ +int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len ); + +/** + * \brief Free an HMAC_DRBG context + * + * \param ctx HMAC_DRBG context to free. + */ +void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx ); + +#if defined(MBEDTLS_FS_IO) +/** + * \brief Write a seed file + * + * \param ctx HMAC_DRBG context + * \param path Name of the file + * + * \return 0 if successful, 1 on file error, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED + */ +int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ); + +/** + * \brief Read and update a seed file. Seed is added to this + * instance + * + * \param ctx HMAC_DRBG context + * \param path Name of the file + * + * \return 0 if successful, 1 on file error, + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or + * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG + */ +int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ); +#endif /* MBEDTLS_FS_IO */ + + +#if defined(MBEDTLS_SELF_TEST) +/** + * \brief Checkup routine + * + * \return 0 if successful, or 1 if the test failed + */ +int mbedtls_hmac_drbg_self_test( int verbose ); +#endif + +#ifdef __cplusplus +} +#endif + +#endif /* hmac_drbg.h */