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	\p is reserved for function parameters. \c is used to describe other values and variables. Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
		
			
				
	
	
		
			447 lines
		
	
	
		
			19 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			447 lines
		
	
	
		
			19 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/**
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 * \file hmac_drbg.h
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 *
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 * \brief The HMAC_DRBG pseudorandom generator.
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 *
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 * This module implements the HMAC_DRBG pseudorandom generator described
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 * in <em>NIST SP 800-90A: Recommendation for Random Number Generation Using
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 * Deterministic Random Bit Generators</em>.
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 */
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/*
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 *  Copyright The Mbed TLS Contributors
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 *  SPDX-License-Identifier: Apache-2.0
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 *
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 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
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 *  not use this file except in compliance with the License.
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 *  You may obtain a copy of the License at
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 *
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 *  http://www.apache.org/licenses/LICENSE-2.0
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 *
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 *  Unless required by applicable law or agreed to in writing, software
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 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 *  See the License for the specific language governing permissions and
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 *  limitations under the License.
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 */
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#ifndef MBEDTLS_HMAC_DRBG_H
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#define MBEDTLS_HMAC_DRBG_H
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#include "mbedtls/private_access.h"
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#include "mbedtls/build_info.h"
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#include "mbedtls/md.h"
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#if defined(MBEDTLS_THREADING_C)
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#include "mbedtls/threading.h"
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#endif
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/*
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 * Error codes
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 */
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/** Too many random requested in single call. */
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#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG              -0x0003
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/** Input too large (Entropy + additional). */
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#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG                -0x0005
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/** Read/write error in file. */
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#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR                -0x0007
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/** The entropy source failed. */
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#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED        -0x0009
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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 mbedtls_config.h or define them on the compiler command line.
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 * \{
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 */
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#if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
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#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL   10000   /**< Interval before reseed is performed by default */
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#endif
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#if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT)
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#define MBEDTLS_HMAC_DRBG_MAX_INPUT         256     /**< Maximum number of additional input bytes */
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#endif
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#if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST)
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#define MBEDTLS_HMAC_DRBG_MAX_REQUEST       1024    /**< Maximum number of requested bytes per call */
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#endif
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#if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT)
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#define MBEDTLS_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 MBEDTLS_HMAC_DRBG_PR_OFF   0   /**< No prediction resistance       */
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#define MBEDTLS_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 mbedtls_hmac_drbg_context {
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    /* Working state: the key K is not stored explicitly,
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     * but is implied by the HMAC context */
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    mbedtls_md_context_t MBEDTLS_PRIVATE(md_ctx);                    /*!< HMAC context (inc. K)  */
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    unsigned char MBEDTLS_PRIVATE(V)[MBEDTLS_MD_MAX_SIZE];  /*!< V in the spec          */
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    int MBEDTLS_PRIVATE(reseed_counter);                     /*!< reseed counter         */
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    /* Administrative state */
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    size_t MBEDTLS_PRIVATE(entropy_len);         /*!< entropy bytes grabbed on each (re)seed */
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    int MBEDTLS_PRIVATE(prediction_resistance);  /*!< enable prediction resistance (Automatic
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                                                    reseed before every random generation) */
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    int MBEDTLS_PRIVATE(reseed_interval);        /*!< reseed interval   */
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    /* Callbacks */
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    int(*MBEDTLS_PRIVATE(f_entropy))(void *, unsigned char *, size_t);  /*!< entropy function */
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    void *MBEDTLS_PRIVATE(p_entropy);            /*!< context for the entropy function        */
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#if defined(MBEDTLS_THREADING_C)
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    /* Invariant: the mutex is initialized if and only if
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     * md_ctx->md_info != NULL. This means that the mutex is initialized
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     * during the initial seeding in mbedtls_hmac_drbg_seed() or
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     * mbedtls_hmac_drbg_seed_buf() and freed in mbedtls_ctr_drbg_free().
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     *
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     * Note that this invariant may change without notice. Do not rely on it
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     * and do not access the mutex directly in application code.
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     */
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    mbedtls_threading_mutex_t MBEDTLS_PRIVATE(mutex);
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#endif
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} mbedtls_hmac_drbg_context;
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/**
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 * \brief               HMAC_DRBG context initialization.
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 *
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 * This function makes the context ready for mbedtls_hmac_drbg_seed(),
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 * mbedtls_hmac_drbg_seed_buf() or mbedtls_hmac_drbg_free().
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 *
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 * \note                The reseed interval is #MBEDTLS_HMAC_DRBG_RESEED_INTERVAL
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 *                      by default. Override this value by calling
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 *                      mbedtls_hmac_drbg_set_reseed_interval().
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 *
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 * \param ctx           HMAC_DRBG context to be initialized.
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 */
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void mbedtls_hmac_drbg_init(mbedtls_hmac_drbg_context *ctx);
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/**
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 * \brief               HMAC_DRBG initial seeding.
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 *
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 * Set the initial seed and set up the entropy source for future reseeds.
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 *
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 * A typical choice for the \p f_entropy and \p p_entropy parameters is
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 * to use the entropy module:
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 * - \p f_entropy is mbedtls_entropy_func();
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 * - \p p_entropy is an instance of ::mbedtls_entropy_context initialized
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 *   with mbedtls_entropy_init() (which registers the platform's default
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 *   entropy sources).
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 *
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 * You can provide a personalization string in addition to the
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 * entropy source, to make this instantiation as unique as possible.
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 *
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 * \note                By default, the security strength as defined by NIST is:
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 *                      - 128 bits if \p md_info is SHA-1;
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 *                      - 192 bits if \p md_info is SHA-224;
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 *                      - 256 bits if \p md_info is SHA-256, SHA-384 or SHA-512.
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 *                      Note that SHA-256 is just as efficient as SHA-224.
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 *                      The security strength can be reduced if a smaller
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 *                      entropy length is set with
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 *                      mbedtls_hmac_drbg_set_entropy_len().
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 *
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 * \note                The default entropy length is the security strength
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 *                      (converted from bits to bytes). You can override
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 *                      it by calling mbedtls_hmac_drbg_set_entropy_len().
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 *
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 * \note                During the initial seeding, this function calls
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 *                      the entropy source to obtain a nonce
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 *                      whose length is half the entropy length.
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 */
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#if defined(MBEDTLS_THREADING_C)
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/**
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 * \note                When Mbed TLS is built with threading support,
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 *                      after this function returns successfully,
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 *                      it is safe to call mbedtls_hmac_drbg_random()
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 *                      from multiple threads. Other operations, including
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 *                      reseeding, are not thread-safe.
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 */
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#endif /* MBEDTLS_THREADING_C */
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/**
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 * \param ctx           HMAC_DRBG context to be seeded.
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 * \param md_info       MD algorithm to use for HMAC_DRBG.
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 * \param f_entropy     The entropy callback, taking as arguments the
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 *                      \p p_entropy context, the buffer to fill, and the
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 *                      length of the buffer.
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 *                      \p f_entropy is always called with a length that is
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 *                      less than or equal to the entropy length.
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 * \param p_entropy     The entropy context to pass to \p f_entropy.
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 * \param custom        The personalization string.
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 *                      This can be \c NULL, in which case the personalization
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 *                      string is empty regardless of the value of \p len.
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 * \param len           The length of the personalization string.
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 *                      This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT
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 *                      and also at most
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 *                      #MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT - \c entropy_len * 3 / 2
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 *                      where \c entropy_len is the entropy length
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 *                      described above.
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 *
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 * \return              \c 0 if successful.
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 * \return              #MBEDTLS_ERR_MD_BAD_INPUT_DATA if \p md_info is
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 *                      invalid.
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 * \return              #MBEDTLS_ERR_MD_ALLOC_FAILED if there was not enough
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 *                      memory to allocate context data.
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 * \return              #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
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 *                      if the call to \p f_entropy failed.
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 */
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int mbedtls_hmac_drbg_seed(mbedtls_hmac_drbg_context *ctx,
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                           const mbedtls_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               Initialisation of simplified HMAC_DRBG (never reseeds).
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 *
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 * This function is meant for use in algorithms that need a pseudorandom
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 * input such as deterministic ECDSA.
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 */
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#if defined(MBEDTLS_THREADING_C)
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/**
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 * \note                When Mbed TLS is built with threading support,
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 *                      after this function returns successfully,
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 *                      it is safe to call mbedtls_hmac_drbg_random()
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 *                      from multiple threads. Other operations, including
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 *                      reseeding, are not thread-safe.
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 */
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#endif /* MBEDTLS_THREADING_C */
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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 the initial entropy string and
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 *                      the additional data.
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 * \param data_len      Length of \p data in bytes.
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 *
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 * \return              \c 0 if successful. or
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 * \return              #MBEDTLS_ERR_MD_BAD_INPUT_DATA if \p md_info is
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 *                      invalid.
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 * \return              #MBEDTLS_ERR_MD_ALLOC_FAILED if there was not enough
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 *                      memory to allocate context data.
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 */
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int mbedtls_hmac_drbg_seed_buf(mbedtls_hmac_drbg_context *ctx,
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                               const mbedtls_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               This function turns prediction resistance on or off.
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 *                      The default value is off.
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 *
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 * \note                If enabled, entropy is gathered at the beginning of
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 *                      every call to mbedtls_hmac_drbg_random_with_add()
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 *                      or mbedtls_hmac_drbg_random().
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 *                      Only use this if your entropy source has sufficient
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 *                      throughput.
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 *
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 * \param ctx           The HMAC_DRBG context.
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 * \param resistance    #MBEDTLS_HMAC_DRBG_PR_ON or #MBEDTLS_HMAC_DRBG_PR_OFF.
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 */
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void mbedtls_hmac_drbg_set_prediction_resistance(mbedtls_hmac_drbg_context *ctx,
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                                                 int resistance);
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/**
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 * \brief               This function sets the amount of entropy grabbed on each
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 *                      seed or reseed.
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 *
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 * See the documentation of mbedtls_hmac_drbg_seed() for the default value.
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 *
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 * \param ctx           The HMAC_DRBG context.
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 * \param len           The amount of entropy to grab, in bytes.
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 */
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void mbedtls_hmac_drbg_set_entropy_len(mbedtls_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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 *
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 * The reseed interval is the number of calls to mbedtls_hmac_drbg_random()
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 * or mbedtls_hmac_drbg_random_with_add() after which the entropy function
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 * is called again.
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 *
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 * The default value is #MBEDTLS_HMAC_DRBG_RESEED_INTERVAL.
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 *
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 * \param ctx           The HMAC_DRBG context.
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 * \param interval      The reseed interval.
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 */
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void mbedtls_hmac_drbg_set_reseed_interval(mbedtls_hmac_drbg_context *ctx,
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                                           int interval);
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/**
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 * \brief               This function updates the state of the HMAC_DRBG context.
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 *
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 * \note                This function is not thread-safe. It is not safe
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 *                      to call this function if another thread might be
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 *                      concurrently obtaining random numbers from the same
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 *                      context or updating or reseeding the same context.
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 *
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 * \param ctx           The HMAC_DRBG context.
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 * \param additional    The data to update the state with.
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 *                      If this is \c NULL, there is no additional data.
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 * \param add_len       Length of \p additional in bytes.
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 *                      Unused if \p additional is \c NULL.
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 *
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 * \return              \c 0 on success, or an error from the underlying
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 *                      hash calculation.
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 */
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int mbedtls_hmac_drbg_update(mbedtls_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               This function reseeds the HMAC_DRBG context, that is
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 *                      extracts data from the entropy source.
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 *
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 * \note                This function is not thread-safe. It is not safe
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 *                      to call this function if another thread might be
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 *                      concurrently obtaining random numbers from the same
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 *                      context or updating or reseeding the same context.
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 *
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 * \param ctx           The HMAC_DRBG context.
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 * \param additional    Additional data to add to the state.
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 *                      If this is \c NULL, there is no additional data
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 *                      and \p len should be \c 0.
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 * \param len           The length of the additional data.
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 *                      This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT
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 *                      and also at most
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 *                      #MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT - \c entropy_len
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 *                      where \c entropy_len is the entropy length
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 *                      (see mbedtls_hmac_drbg_set_entropy_len()).
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 *
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 * \return              \c 0 if successful.
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 * \return              #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
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 *                      if a call to the entropy function failed.
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 */
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int mbedtls_hmac_drbg_reseed(mbedtls_hmac_drbg_context *ctx,
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                             const unsigned char *additional, size_t len);
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/**
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 * \brief   This function updates an HMAC_DRBG instance with additional
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 *          data and uses it to generate random data.
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 *
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 * This function automatically reseeds if the reseed counter is exceeded
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 * or prediction resistance is enabled.
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 *
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 * \note                This function is not thread-safe. It is not safe
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 *                      to call this function if another thread might be
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 *                      concurrently obtaining random numbers from the same
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 *                      context or updating or reseeding the same context.
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 *
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 * \param p_rng         The HMAC_DRBG context. This must be a pointer to a
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 *                      #mbedtls_hmac_drbg_context structure.
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 * \param output        The buffer to fill.
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 * \param output_len    The length of the buffer in bytes.
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 *                      This must be at most #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
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 * \param additional    Additional data to update with.
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 *                      If this is \c NULL, there is no additional data
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 *                      and \p add_len should be \c 0.
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 * \param add_len       The length of the additional data.
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 *                      This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT.
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 *
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 * \return              \c 0 if successful.
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 * \return              #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
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 *                      if a call to the entropy source failed.
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 * \return              #MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG if
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 *                      \p output_len > #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
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 * \return              #MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG if
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 *                      \p add_len > #MBEDTLS_HMAC_DRBG_MAX_INPUT.
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 */
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int mbedtls_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   This function uses HMAC_DRBG to generate random data.
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 *
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 * This function automatically reseeds if the reseed counter is exceeded
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 * or prediction resistance is enabled.
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 */
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#if defined(MBEDTLS_THREADING_C)
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/**
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 * \note                When Mbed TLS is built with threading support,
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 *                      it is safe to call mbedtls_ctr_drbg_random()
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 *                      from multiple threads. Other operations, including
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 *                      reseeding, are not thread-safe.
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 */
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#endif /* MBEDTLS_THREADING_C */
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/**
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 * \param p_rng         The HMAC_DRBG context. This must be a pointer to a
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 *                      #mbedtls_hmac_drbg_context structure.
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 * \param output        The buffer to fill.
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 * \param out_len       The length of the buffer in bytes.
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						|
 *                      This must be at most #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
 | 
						|
 *
 | 
						|
 * \return              \c 0 if successful.
 | 
						|
 * \return              #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
 | 
						|
 *                      if a call to the entropy source failed.
 | 
						|
 * \return              #MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG if
 | 
						|
 *                      \p out_len > #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
 | 
						|
 */
 | 
						|
int mbedtls_hmac_drbg_random(void *p_rng, unsigned char *output, size_t out_len);
 | 
						|
 | 
						|
/**
 | 
						|
 * \brief               This function resets HMAC_DRBG context to the state immediately
 | 
						|
 *                      after initial call of mbedtls_hmac_drbg_init().
 | 
						|
 *
 | 
						|
 * \param ctx           The HMAC_DRBG context to free.
 | 
						|
 */
 | 
						|
void mbedtls_hmac_drbg_free(mbedtls_hmac_drbg_context *ctx);
 | 
						|
 | 
						|
#if defined(MBEDTLS_FS_IO)
 | 
						|
/**
 | 
						|
 * \brief               This function writes a seed file.
 | 
						|
 *
 | 
						|
 * \param ctx           The HMAC_DRBG context.
 | 
						|
 * \param path          The name of the file.
 | 
						|
 *
 | 
						|
 * \return              \c 0 on success.
 | 
						|
 * \return              #MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR on file error.
 | 
						|
 * \return              #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED on reseed
 | 
						|
 *                      failure.
 | 
						|
 */
 | 
						|
int mbedtls_hmac_drbg_write_seed_file(mbedtls_hmac_drbg_context *ctx, const char *path);
 | 
						|
 | 
						|
/**
 | 
						|
 * \brief               This function reads and updates a seed file. The seed
 | 
						|
 *                      is added to this instance.
 | 
						|
 *
 | 
						|
 * \param ctx           The HMAC_DRBG context.
 | 
						|
 * \param path          The name of the file.
 | 
						|
 *
 | 
						|
 * \return              \c 0 on success.
 | 
						|
 * \return              #MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR on file error.
 | 
						|
 * \return              #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED on
 | 
						|
 *                      reseed failure.
 | 
						|
 * \return              #MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG if the existing
 | 
						|
 *                      seed file is too large.
 | 
						|
 */
 | 
						|
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               The HMAC_DRBG Checkup routine.
 | 
						|
 *
 | 
						|
 * \return              \c 0 if successful.
 | 
						|
 * \return              \c 1 if the test failed.
 | 
						|
 */
 | 
						|
int mbedtls_hmac_drbg_self_test(int verbose);
 | 
						|
#endif
 | 
						|
 | 
						|
#ifdef __cplusplus
 | 
						|
}
 | 
						|
#endif
 | 
						|
 | 
						|
#endif /* hmac_drbg.h */
 |