Documentation

Documentation

Includes

config.h

#include "config.h"
#include "config.h"

MBEDTLS_CONFIG_FILE

#include MBEDTLS_CONFIG_FILE
#include MBEDTLS_CONFIG_FILE

md.h

#include "md.h"
#include "md.h"

threading.h

#include "threading.h"
#include "threading.h"

Macros

Marco MBEDTLS_HMAC_DRBG_H

#define MBEDTLS_HMAC_DRBG_H


      

Marco MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG

#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG             -3 /**< Too many random requested in single call. */
/*
 * Error codes
 */

Marco MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG

#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG               -5 /**< Input too large (Entropy + additional). */


      

Marco MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR

#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR               -7 /**< Read/write error in file. */


      

Marco MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED

#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED       -9 /**< The entropy source failed. */


      

Marco MBEDTLS_HMAC_DRBG_RESEED_INTERVAL

#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL  10000  /**< Interval before reseed is performed by default */


      

Marco MBEDTLS_HMAC_DRBG_MAX_INPUT

#define MBEDTLS_HMAC_DRBG_MAX_INPUT        256    /**< Maximum number of additional input bytes */


      

Marco MBEDTLS_HMAC_DRBG_MAX_REQUEST

#define MBEDTLS_HMAC_DRBG_MAX_REQUEST      1024   /**< Maximum number of requested bytes per call */


      

Marco MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT

#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT   384    /**< Maximum size of (re)seed buffer */


      

Marco MBEDTLS_HMAC_DRBG_PR_OFF

#define MBEDTLS_HMAC_DRBG_PR_OFF  0  /**< No prediction resistance       */


      

Marco MBEDTLS_HMAC_DRBG_PR_ON

#define MBEDTLS_HMAC_DRBG_PR_ON   1  /**< Prediction resistance enabled  */


      

Marco MBEDTLS_DEPRECATED

#define MBEDTLS_DEPRECATED   __attribute__((deprecated))


      

Marco MBEDTLS_DEPRECATED

#define MBEDTLS_DEPRECATED

      

Functions

Func mbedtls_hmac_drbg_init

void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx );
/**
 * \brief               HMAC_DRBG context initialization
 *                      Makes the context ready for mbedtls_hmac_drbg_seed(),
 *                      mbedtls_hmac_drbg_seed_buf() or
 *                      mbedtls_hmac_drbg_free().
 *
 * \param ctx           HMAC_DRBG context to be initialized
 */

Func mbedtls_hmac_drbg_seed

int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx,
                   const mbedtls_md_info_t * md_info,
                   int (*f_entropy)(void *, unsigned char *, size_t),
                   void *p_entropy,
                   const unsigned char *custom,
                   size_t len );
/**
 * \brief               HMAC_DRBG initial seeding
 *                      Seed and setup entropy source for future reseeds.
 *
 * \param ctx           HMAC_DRBG context to be seeded
 * \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
 *                      MBEDTLS_ERR_MD_BAD_INPUT_DATA, or
 *                      MBEDTLS_ERR_MD_ALLOC_FAILED, or
 *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED.
 */

Func mbedtls_hmac_drbg_seed_buf

int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx,
                       const mbedtls_md_info_t * md_info,
                       const unsigned char *data, size_t data_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
 *                      MBEDTLS_ERR_MD_BAD_INPUT_DATA, or
 *                      MBEDTLS_ERR_MD_ALLOC_FAILED.
 */

Func mbedtls_hmac_drbg_set_prediction_resistance

void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx,
                                         int resistance );
/**
 * \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    MBEDTLS_HMAC_DRBG_PR_ON or MBEDTLS_HMAC_DRBG_PR_OFF
 */

Func mbedtls_hmac_drbg_set_entropy_len

void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx,
                               size_t len );
/**
 * \brief               Set the amount of entropy grabbed on each reseed
 *                      (Default: given by the security strength, which
 *                      depends on the hash used, see \c mbedtls_hmac_drbg_init() )
 *
 * \param ctx           HMAC_DRBG context
 * \param len           Amount of entropy to grab, in bytes
 */

Func mbedtls_hmac_drbg_set_reseed_interval

void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx,
                                   int interval );
/**
 * \brief               Set the reseed interval
 *                      (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
 *
 * \param ctx           HMAC_DRBG context
 * \param interval      Reseed interval
 */

Func mbedtls_hmac_drbg_update_ret

int mbedtls_hmac_drbg_update_ret( mbedtls_hmac_drbg_context *ctx,
                      const unsigned char *additional, size_t add_len );
/**
 * \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
 *
 * \return              \c 0 on success, or an error from the underlying
 *                      hash calculation.
 *
 * \note                Additional data is optional, pass NULL and 0 as second
 *                      third argument if no additional data is being used.
 */

Func mbedtls_hmac_drbg_reseed

int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx,
                     const unsigned char *additional, size_t 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
 *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
 */

Func mbedtls_hmac_drbg_random_with_add

int mbedtls_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 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
 *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
 *                      MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or
 *                      MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG.
 */

Func mbedtls_hmac_drbg_random

int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_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
 *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
 *                      MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG
 */

Func mbedtls_hmac_drbg_free

void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx );
/**
 * \brief               Free an HMAC_DRBG context
 *
 * \param ctx           HMAC_DRBG context to free.
 */

Func mbedtls_hmac_drbg_write_seed_file

int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
/**
 * \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
 *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
 */

Func mbedtls_hmac_drbg_update_seed_file

int mbedtls_hmac_drbg_update_seed_file( mbedtls_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,
 *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or
 *                      MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG
 */

Func mbedtls_hmac_drbg_self_test

int mbedtls_hmac_drbg_self_test( int verbose );
/**
 * \brief               Checkup routine
 *
 * \return              0 if successful, or 1 if the test failed
 */

Vars

Variable MBEDTLS_DEPRECATED

MBEDTLS_DEPRECATED void mbedtls_hmac_drbg_update(
   mbedtls_hmac_drbg_context *ctx,
   const unsigned char *additional, size_t add_len );
/**
 * \brief               HMAC_DRBG update state
 *
 * \deprecated          Superseded by mbedtls_hmac_drbg_update_ret()
 *                      in 2.16.0.
 *
 * \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.
 */

Consts

Types

Typedefs

Typedef mbedtls_hmac_drbg_context;

typedef struct mbedtls_hmac_drbg_context
{
   /* Working state: the key K is not stored explicitely,
     * but is implied by the HMAC context */
   mbedtls_md_context_t md_ctx;                   /*!< HMAC context (inc. K)  */
   unsigned char V[MBEDTLS_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        */

#if defined(MBEDTLS_THREADING_C)
   mbedtls_threading_mutex_t mutex;
#endif
} mbedtls_hmac_drbg_context;
/**
 * HMAC_DRBG context.
 */