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Add automatic periodic reseeding

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This commit is contained in:
Manuel Pégourié-Gonnard 2014-01-30 19:03:45 +01:00
parent af786ff6cc
commit 658dbed080
2 changed files with 40 additions and 12 deletions
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31
include/polarssl/hmac_drbg.h
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@ -51,18 +51,22 @@ extern "C" {
/**
* HMAC_DRBG context.
* TODO: reseed counter.
*/
typedef struct
{
md_context_t md_ctx;
unsigned char V[POLARSSL_MD_MAX_SIZE];
unsigned char K[POLARSSL_MD_MAX_SIZE];
/* Working state */
md_context_t md_ctx; /*!< HMAC context */
unsigned char V[POLARSSL_MD_MAX_SIZE]; /*!< V in the spec */
unsigned char K[POLARSSL_MD_MAX_SIZE]; /*!< Key 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 */
} hmac_drbg_context;
@ -128,14 +132,25 @@ void hmac_drbg_set_prediction_resistance( hmac_drbg_context *ctx,
/**
* \brief Set the amount of entropy grabbed on each reseed
* (Default: HMAC_DRBG_ENTROPY_LEN)
* (Default: given by the security strength, which
* depends on the hash used, see \c hmac_drbg_init() )
*
* \param ctx HMAC_DRBG context
* \param len Amount of entropy to grab
* \param len Amount of entropy to grab, in bytes
*/
void hmac_drbg_set_entropy_len( hmac_drbg_context *ctx,
size_t len );
/**
* \brief Set the reseed interval
* (Default: HMAC_DRBG_RESEED_INTERVAL)
*
* \param ctx HMAC_DRBG context
* \param interval Reseed interval
*/
void hmac_drbg_set_reseed_interval( hmac_drbg_context *ctx,
int interval );
/**
* \brief HMAC_DRBG update state
*
@ -165,7 +180,7 @@ int hmac_drbg_reseed( hmac_drbg_context *ctx,
/**
* \brief HMAC_DRBG generate random with additional update input
*
* Note: Automatically reseeds if reseed_counter is reached.
* Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
*
* \param p_rng HMAC_DRBG context
* \param output Buffer to fill
@ -185,7 +200,7 @@ int hmac_drbg_random_with_add( void *p_rng,
/**
* \brief HMAC_DRBG generate random
*
* Note: Automatically reseeds if reseed_counter is reached.
* Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
*
* \param p_rng HMAC_DRBG context
* \param output Buffer to fill