285 lines
10 KiB
C
285 lines
10 KiB
C
/**
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* \file hmac_drbg.h
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*
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* \brief HMAC_DRBG (NIST SP 800-90A)
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*
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* Copyright (C) 2014, Brainspark B.V.
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*
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* This file is part of PolarSSL (http://www.polarssl.org)
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* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef POLARSSL_HMAC_DRBG_H
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#define POLARSSL_HMAC_DRBG_H
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#include "md.h"
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/*
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* Error codes
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*/
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#define POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */
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#define POLARSSL_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */
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#define POLARSSL_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */
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#define POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED -0x0009 /**< The entropy source failed. */
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/**
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* \name SECTION: Module settings
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*
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* The configuration options you can set for this module are in this section.
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* Either change them in config.h or define them on the compiler command line.
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* \{
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*/
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#if !defined(POLARSSL_HMAC_DRBG_RESEED_INTERVAL)
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#define POLARSSL_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */
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#endif
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#if !defined(POLARSSL_HMAC_DRBG_MAX_INPUT)
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#define POLARSSL_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */
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#endif
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#if !defined(POLARSSL_HMAC_DRBG_MAX_REQUEST)
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#define POLARSSL_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */
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#endif
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#if !defined(POLARSSL_HMAC_DRBG_MAX_SEED_INPUT)
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#define POLARSSL_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */
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#endif
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/* \} name SECTION: Module settings */
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#define POLARSSL_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */
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#define POLARSSL_HMAC_DRBG_PR_ON 1 /**< Prediction resistance enabled */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* HMAC_DRBG context.
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*/
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typedef struct
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{
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/* Working state: the key K is not stored explicitely,
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* but is implied by the HMAC context */
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md_context_t md_ctx; /*!< HMAC context (inc. K) */
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unsigned char V[POLARSSL_MD_MAX_SIZE]; /*!< V in the spec */
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int reseed_counter; /*!< reseed counter */
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/* Administrative state */
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size_t entropy_len; /*!< entropy bytes grabbed on each (re)seed */
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int prediction_resistance; /*!< enable prediction resistance (Automatic
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reseed before every random generation) */
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int reseed_interval; /*!< reseed interval */
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/* Callbacks */
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int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */
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void *p_entropy; /*!< context for the entropy function */
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} hmac_drbg_context;
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/**
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* \brief HMAC_DRBG initialisation
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*
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* \param ctx HMAC_DRBG context to be initialised
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* \param md_info MD algorithm to use for HMAC_DRBG
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* \param f_entropy Entropy callback (p_entropy, buffer to fill, buffer
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* length)
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* \param p_entropy Entropy context
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* \param custom Personalization data (Device specific identifiers)
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* (Can be NULL)
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* \param len Length of personalization data
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*
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* \note The "security strength" as defined by NIST is set to:
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* 128 bits if md_alg is SHA-1,
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* 192 bits if md_alg is SHA-224,
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* 256 bits if md_alg is SHA-256 or higher.
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* Note that SHA-256 is just as efficient as SHA-224.
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*
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* \return 0 if successful, or
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* POLARSSL_ERR_MD_BAD_INPUT_DATA, or
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* POLARSSL_ERR_MD_ALLOC_FAILED, or
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* POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED.
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*/
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int hmac_drbg_init( hmac_drbg_context *ctx,
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const md_info_t * md_info,
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int (*f_entropy)(void *, unsigned char *, size_t),
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void *p_entropy,
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const unsigned char *custom,
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size_t len );
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/**
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* \brief Initilisation of simpified HMAC_DRBG (never reseeds).
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* (For use with deterministic ECDSA.)
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*
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* \param ctx HMAC_DRBG context to be initialised
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* \param md_info MD algorithm to use for HMAC_DRBG
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* \param data Concatenation of entropy string and additional data
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* \param data_len Length of data in bytes
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*
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* \return 0 if successful, or
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* POLARSSL_ERR_MD_BAD_INPUT_DATA, or
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* POLARSSL_ERR_MD_ALLOC_FAILED.
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*/
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int hmac_drbg_init_buf( hmac_drbg_context *ctx,
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const md_info_t * md_info,
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const unsigned char *data, size_t data_len );
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/**
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* \brief Enable / disable prediction resistance (Default: Off)
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*
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* Note: If enabled, entropy is used for ctx->entropy_len before each call!
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* Only use this if you have ample supply of good entropy!
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*
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* \param ctx HMAC_DRBG context
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* \param resistance POLARSSL_HMAC_DRBG_PR_ON or POLARSSL_HMAC_DRBG_PR_OFF
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*/
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void hmac_drbg_set_prediction_resistance( hmac_drbg_context *ctx,
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int resistance );
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/**
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* \brief Set the amount of entropy grabbed on each reseed
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* (Default: given by the security strength, which
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* depends on the hash used, see \c hmac_drbg_init() )
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*
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* \param ctx HMAC_DRBG context
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* \param len Amount of entropy to grab, in bytes
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*/
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void hmac_drbg_set_entropy_len( hmac_drbg_context *ctx,
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size_t len );
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/**
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* \brief Set the reseed interval
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* (Default: POLARSSL_HMAC_DRBG_RESEED_INTERVAL)
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*
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* \param ctx HMAC_DRBG context
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* \param interval Reseed interval
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*/
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void hmac_drbg_set_reseed_interval( hmac_drbg_context *ctx,
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int interval );
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/**
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* \brief HMAC_DRBG update state
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*
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* \param ctx HMAC_DRBG context
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* \param additional Additional data to update state with, or NULL
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* \param add_len Length of additional data, or 0
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*
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* \note Additional data is optional, pass NULL and 0 as second
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* third argument if no additional data is being used.
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*/
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void hmac_drbg_update( hmac_drbg_context *ctx,
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const unsigned char *additional, size_t add_len );
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/**
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* \brief HMAC_DRBG reseeding (extracts data from entropy source)
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*
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* \param ctx HMAC_DRBG context
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* \param additional Additional data to add to state (Can be NULL)
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* \param len Length of additional data
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*
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* \return 0 if successful, or
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* POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
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*/
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int hmac_drbg_reseed( hmac_drbg_context *ctx,
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const unsigned char *additional, size_t len );
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/**
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* \brief HMAC_DRBG generate random with additional update input
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*
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* Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
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*
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* \param p_rng HMAC_DRBG context
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* \param output Buffer to fill
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* \param output_len Length of the buffer
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* \param additional Additional data to update with (can be NULL)
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* \param add_len Length of additional data (can be 0)
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*
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* \return 0 if successful, or
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* POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
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* POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or
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* POLARSSL_ERR_HMAC_DRBG_INPUT_TOO_BIG.
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*/
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int hmac_drbg_random_with_add( void *p_rng,
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unsigned char *output, size_t output_len,
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const unsigned char *additional,
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size_t add_len );
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/**
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* \brief HMAC_DRBG generate random
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*
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* Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
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*
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* \param p_rng HMAC_DRBG context
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* \param output Buffer to fill
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* \param out_len Length of the buffer
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*
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* \return 0 if successful, or
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* POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
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* POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG
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*/
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int hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len );
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/**
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* \brief Free an HMAC_DRBG context
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*
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* \param ctx HMAC_DRBG context to free.
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*/
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void hmac_drbg_free( hmac_drbg_context *ctx );
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#if defined(POLARSSL_FS_IO)
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/**
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* \brief Write a seed file
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*
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* \param ctx HMAC_DRBG context
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* \param path Name of the file
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*
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* \return 0 if successful, 1 on file error, or
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* POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
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*/
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int hmac_drbg_write_seed_file( hmac_drbg_context *ctx, const char *path );
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/**
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* \brief Read and update a seed file. Seed is added to this
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* instance
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*
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* \param ctx HMAC_DRBG context
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* \param path Name of the file
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*
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* \return 0 if successful, 1 on file error,
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* POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or
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* POLARSSL_ERR_HMAC_DRBG_INPUT_TOO_BIG
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*/
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int hmac_drbg_update_seed_file( hmac_drbg_context *ctx, const char *path );
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#endif /* POLARSSL_FS_IO */
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#if defined(POLARSSL_SELF_TEST)
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/**
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* \brief Checkup routine
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*
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* \return 0 if successful, or 1 if the test failed
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*/
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int hmac_drbg_self_test( int verbose );
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* hmac_drbg.h */
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