| /** |
| * \file hmac_drbg.h |
| * |
| * \brief HMAC_DRBG (NIST SP 800-90A) |
| * |
| * Copyright (C) 2014, Brainspark B.V. |
| * |
| * This file is part of PolarSSL (http://www.polarssl.org) |
| * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org> |
| * |
| * All rights reserved. |
| * |
| * 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_HMAC_DRBG_H |
| #define POLARSSL_HMAC_DRBG_H |
| |
| #include "md.h" |
| |
| /* |
| * Error codes |
| */ |
| #define POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */ |
| #define POLARSSL_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */ |
| #define POLARSSL_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */ |
| #define POLARSSL_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(POLARSSL_HMAC_DRBG_RESEED_INTERVAL) |
| #define POLARSSL_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */ |
| #endif |
| |
| #if !defined(POLARSSL_HMAC_DRBG_MAX_INPUT) |
| #define POLARSSL_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */ |
| #endif |
| |
| #if !defined(POLARSSL_HMAC_DRBG_MAX_REQUEST) |
| #define POLARSSL_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */ |
| #endif |
| |
| #if !defined(POLARSSL_HMAC_DRBG_MAX_SEED_INPUT) |
| #define POLARSSL_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */ |
| #endif |
| |
| /* \} name SECTION: Module settings */ |
| |
| #define POLARSSL_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */ |
| #define POLARSSL_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 */ |
| md_context_t md_ctx; /*!< HMAC context (inc. K) */ |
| unsigned char V[POLARSSL_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 */ |
| } hmac_drbg_context; |
| |
| /** |
| * \brief HMAC_DRBG initialisation |
| * |
| * \param ctx HMAC_DRBG context to be initialised |
| * \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 |
| * POLARSSL_ERR_MD_BAD_INPUT_DATA, or |
| * POLARSSL_ERR_MD_ALLOC_FAILED, or |
| * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED. |
| */ |
| int hmac_drbg_init( hmac_drbg_context *ctx, |
| const 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 |
| * POLARSSL_ERR_MD_BAD_INPUT_DATA, or |
| * POLARSSL_ERR_MD_ALLOC_FAILED. |
| */ |
| int hmac_drbg_init_buf( hmac_drbg_context *ctx, |
| const 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 POLARSSL_HMAC_DRBG_PR_ON or POLARSSL_HMAC_DRBG_PR_OFF |
| */ |
| void hmac_drbg_set_prediction_resistance( 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 hmac_drbg_init() ) |
| * |
| * \param ctx HMAC_DRBG context |
| * \param len Amount of entropy to grab, in bytes |
| */ |
| void hmac_drbg_set_entropy_len( hmac_drbg_context *ctx, |
| size_t len ); |
| |
| /** |
| * \brief Set the reseed interval |
| * (Default: POLARSSL_HMAC_DRBG_RESEED_INTERVAL) |
| * |
| * \param ctx HMAC_DRBG context |
| * \param interval Reseed interval |
| */ |
| void hmac_drbg_set_reseed_interval( 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 hmac_drbg_update( 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 |
| * POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED |
| */ |
| int hmac_drbg_reseed( 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 |
| * POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or |
| * POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or |
| * POLARSSL_ERR_HMAC_DRBG_INPUT_TOO_BIG. |
| */ |
| int 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 |
| * POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or |
| * POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG |
| */ |
| int 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 hmac_drbg_free( hmac_drbg_context *ctx ); |
| |
| #if defined(POLARSSL_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 |
| * POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED |
| */ |
| int hmac_drbg_write_seed_file( 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, |
| * POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or |
| * POLARSSL_ERR_HMAC_DRBG_INPUT_TOO_BIG |
| */ |
| int hmac_drbg_update_seed_file( hmac_drbg_context *ctx, const char *path ); |
| #endif /* POLARSSL_FS_IO */ |
| |
| |
| #if defined(POLARSSL_SELF_TEST) |
| /** |
| * \brief Checkup routine |
| * |
| * \return 0 if successful, or 1 if the test failed |
| */ |
| int hmac_drbg_self_test( int verbose ); |
| #endif |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* hmac_drbg.h */ |
