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Diffstat (limited to 'polarssl/src/include/polarssl/ctr_drbg.h')
| -rw-r--r-- | polarssl/src/include/polarssl/ctr_drbg.h | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/polarssl/src/include/polarssl/ctr_drbg.h b/polarssl/src/include/polarssl/ctr_drbg.h new file mode 100644 index 0000000..83861a9 --- /dev/null +++ b/polarssl/src/include/polarssl/ctr_drbg.h @@ -0,0 +1,228 @@ +/** + * \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 */ |