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Add hmac_drbg_set_prediction_resistance()

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This commit is contained in:
Manuel Pégourié-Gonnard
2014-01-30 18:44:18 +01:00
parent 8fc484d1df
commit af786ff6cc
2 changed files with 37 additions and 7 deletions
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18
library/hmac_drbg.c
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@ -170,6 +170,15 @@ int hmac_drbg_init( hmac_drbg_context *ctx,
return( 0 );
}
/*
* Set prediction resistance
*/
void hmac_drbg_set_prediction_resistance( hmac_drbg_context *ctx,
int resistance )
{
ctx->prediction_resistance = resistance;
}
/*
* Set entropy length grabbed for reseeds
*/
@ -185,12 +194,19 @@ int hmac_drbg_random_with_add( void *p_rng,
unsigned char *output, size_t out_len,
const unsigned char *additional, size_t add_len )
{
int ret;
hmac_drbg_context *ctx = (hmac_drbg_context *) p_rng;
size_t md_len = md_get_size( ctx->md_ctx.md_info );
size_t left = out_len;
unsigned char *out = output;
/* 1. Check reseed counter (TODO) */
/* 1. Check reseed counter (TODO) and PR */
if( ctx->f_entropy != NULL &&
ctx->prediction_resistance == HMAC_DRBG_PR_ON )
{
if( ( ret = hmac_drbg_reseed( ctx, additional, add_len ) ) != 0 )
return( ret );
}
/* 2. Use additional data if any */
if( additional != NULL && add_len != 0 )