| /** |
| * \file ctr_drbg.h |
| * |
| * \brief CTR_DRBG based on AES-256 (NIST SP 800-90) |
| * |
| * Copyright (C) 2006-2010, 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_CTR_DRBG_H |
| #define POLARSSL_CTR_DRBG_H |
| |
| #include <string.h> |
| |
| #include "aes.h" |
| |
| #define POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED -0x0034 /**< The entropy source failed. */ |
| #define POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG -0x0036 /**< Too many random requested in single call. */ |
| #define POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG -0x0038 /**< Input too large (Entropy + additional). */ |
| #define POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR -0x003A /**< Read/write error in file. */ |
| |
| #define CTR_DRBG_BLOCKSIZE 16 /**< Block size used by the cipher */ |
| #define CTR_DRBG_KEYSIZE 32 /**< Key size used by the cipher */ |
| #define CTR_DRBG_KEYBITS ( CTR_DRBG_KEYSIZE * 8 ) |
| #define CTR_DRBG_SEEDLEN ( CTR_DRBG_KEYSIZE + CTR_DRBG_BLOCKSIZE ) |
| /**< The seed length (counter + AES key) */ |
| #define CTR_DRBG_ENTROPY_LEN 48 /**< Amount of entropy used per seed by default */ |
| #define CTR_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */ |
| #define CTR_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */ |
| #define CTR_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */ |
| #define CTR_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */ |
| |
| #define CTR_DRBG_PR_OFF 0 /**< No prediction resistance */ |
| #define CTR_DRBG_PR_ON 1 /**< Prediction resistance enabled */ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** |
| * \brief CTR_DRBG context structure |
| */ |
| typedef struct |
| { |
| unsigned char counter[16]; /*!< counter (V) */ |
| int reseed_counter; /*!< reseed counter */ |
| int prediction_resistance; /*!< enable prediction resistance (Automatic |
| reseed before every random generation) */ |
| size_t entropy_len; /*!< amount of entropy grabbed on each (re)seed */ |
| int reseed_interval; /*!< reseed interval */ |
| |
| aes_context aes_ctx; /*!< AES context */ |
| |
| /* |
| * Callbacks (Entropy) |
| */ |
| int (*f_entropy)(void *, unsigned char *, size_t); |
| |
| void *p_entropy; /*!< context for the entropy function */ |
| } |
| ctr_drbg_context; |
| |
| /** |
| * \brief CTR_DRBG initialization |
| * |
| * Note: Personalization data can be provided in addition to the more generic |
| * entropy source to make this instantiation as unique as possible. |
| * |
| * \param ctx CTR_DRBG context to be initialized |
| * \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 |
| * |
| * \return 0 if successful, or |
| * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED |
| */ |
| int ctr_drbg_init( ctr_drbg_context *ctx, |
| int (*f_entropy)(void *, unsigned char *, size_t), |
| void *p_entropy, |
| const unsigned char *custom, |
| size_t 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 CTR_DRBG context |
| * \param resistance CTR_DRBG_PR_ON or CTR_DRBG_PR_OFF |
| */ |
| void ctr_drbg_set_prediction_resistance( ctr_drbg_context *ctx, |
| int resistance ); |
| |
| /** |
| * \brief Set the amount of entropy grabbed on each (re)seed |
| * (Default: CTR_DRBG_ENTROPY_LEN) |
| * |
| * \param ctx CTR_DRBG context |
| * \param len Amount of entropy to grab |
| */ |
| void ctr_drbg_set_entropy_len( ctr_drbg_context *ctx, |
| size_t len ); |
| |
| /** |
| * \brief Set the reseed interval |
| * (Default: CTR_DRBG_RESEED_INTERVAL) |
| * |
| * \param ctx CTR_DRBG context |
| * \param interval Reseed interval |
| */ |
| void ctr_drbg_set_reseed_interval( ctr_drbg_context *ctx, |
| int interval ); |
| |
| /** |
| * \brief CTR_DRBG reseeding (extracts data from entropy source) |
| * |
| * \param ctx CTR_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_CTR_DRBG_ENTROPY_SOURCE_FAILED |
| */ |
| int ctr_drbg_reseed( ctr_drbg_context *ctx, |
| const unsigned char *additional, size_t len ); |
| |
| /** |
| * \brief CTR_DRBG update state |
| * |
| * \param ctx CTR_DRBG context |
| * \param additional Additional data to update state with |
| * \param add_len Length of additional data |
| */ |
| void ctr_drbg_update( ctr_drbg_context *ctx, |
| const unsigned char *additional, size_t add_len ); |
| |
| /** |
| * \brief CTR_DRBG generate random with additional update input |
| * |
| * Note: Automatically reseeds if reseed_counter is reached. |
| * |
| * \param p_rng CTR_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 |
| * |
| * \return 0 if successful, or |
| * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED, or |
| * POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG |
| */ |
| int ctr_drbg_random_with_add( void *p_rng, |
| unsigned char *output, size_t output_len, |
| const unsigned char *additional, size_t add_len ); |
| |
| /** |
| * \brief CTR_DRBG generate random |
| * |
| * Note: Automatically reseeds if reseed_counter is reached. |
| * |
| * \param p_rng CTR_DRBG context |
| * \param output Buffer to fill |
| * \param output_len Length of the buffer |
| * |
| * \return 0 if successful, or |
| * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED, or |
| * POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG |
| */ |
| int ctr_drbg_random( void *p_rng, |
| unsigned char *output, size_t output_len ); |
| |
| #if defined(POLARSSL_FS_IO) |
| /** |
| * \brief Write a seed file |
| * |
| * \param path Name of the file |
| * |
| * \return 0 if successful, 1 on file error, or |
| * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED |
| */ |
| int ctr_drbg_write_seed_file( ctr_drbg_context *ctx, const char *path ); |
| |
| /** |
| * \brief Read and update a seed file. Seed is added to this |
| * instance |
| * |
| * \param path Name of the file |
| * |
| * \return 0 if successful, 1 on file error, |
| * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED or |
| * POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG |
| */ |
| int ctr_drbg_update_seed_file( ctr_drbg_context *ctx, const char *path ); |
| #endif |
| |
| /** |
| * \brief Checkup routine |
| * |
| * \return 0 if successful, or 1 if the test failed |
| */ |
| int ctr_drbg_self_test( int verbose ); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* ctr_drbg.h */ |