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Add hmac_random_with_add()

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This commit is contained in:
Manuel Pégourié-Gonnard 2014-01-30 12:19:26 +01:00
parent 7845fc06c9
commit 8208d167da
2 changed files with 54 additions and 8 deletions
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26
include/polarssl/hmac_drbg.h
View File

@ -75,16 +75,38 @@ int hmac_drbg_init( hmac_drbg_context *ctx,
void hmac_drbg_update( hmac_drbg_context *ctx,
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.
*
* \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
* TODO: POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
* TODO: POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG
*/
int 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
*
* Note: Automatically reseeds if reseed_counter is reached. (TODO)
* Note: Automatically reseeds if reseed_counter is reached.
*
* \param p_rng HMAC_DRBG context
* \param output Buffer to fill
* \param output_len Length of the buffer
*
* \return 0 if successful.
* \return 0 if successful, or
* TODO: POLARSSL_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
* TODO: POLARSSL_ERR_HMAC_DRBG_REQUEST_TOO_BIG
*/
int hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len );

36
library/hmac_drbg.c
View File

@ -24,8 +24,9 @@
*/
/*
* The NIST SP 800-90 DRBGs are described in the following publication.
* The NIST SP 800-90A DRBGs are described in the following publication.
* http://csrc.nist.gov/publications/nistpubs/800-90A/SP800-90A.pdf
* References below are based on rev. 1 (January 2012).
*/
#include "polarssl/config.h"
@ -35,7 +36,7 @@
#include "polarssl/hmac_drbg.h"
/*
* HMAC_DRBG update, using optional additional data
* HMAC_DRBG update, using optional additional data (10.1.2.2)
*/
void hmac_drbg_update( hmac_drbg_context *ctx,
const unsigned char *additional, size_t add_len )
@ -46,6 +47,7 @@ void hmac_drbg_update( hmac_drbg_context *ctx,
for( sep[0] = 0; sep[0] < rounds; sep[0]++ )
{
/* Step 1 or 4 */
md_hmac_starts( &ctx->md_ctx, ctx->K, md_len );
md_hmac_update( &ctx->md_ctx, ctx->V, md_len );
md_hmac_update( &ctx->md_ctx, sep, 1 );
@ -53,6 +55,7 @@ void hmac_drbg_update( hmac_drbg_context *ctx,
md_hmac_update( &ctx->md_ctx, additional, add_len );
md_hmac_finish( &ctx->md_ctx, ctx->K );
/* Step 2 or 5 */
md_hmac_starts( &ctx->md_ctx, ctx->K, md_len );
md_hmac_update( &ctx->md_ctx, ctx->V, md_len );
md_hmac_finish( &ctx->md_ctx, ctx->V );
@ -82,15 +85,24 @@ int hmac_drbg_init( hmac_drbg_context *ctx,
}
/*
* Simplified HMAC_DRBG random function
* HMAC_DRBG random function with optional additional data (10.1.2.5)
*/
int hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len )
int hmac_drbg_random_with_add( void *p_rng,
unsigned char *output, size_t out_len,
const unsigned char *additional, size_t add_len )
{
hmac_drbg_context *ctx = (hmac_drbg_context *) p_rng;
size_t md_len = ctx->md_ctx.md_info->size;
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) */
/* 2. Use additional data if any */
if( additional != NULL && add_len != 0 )
hmac_drbg_update( ctx, additional, add_len );
/* 3, 4, 5. Generate bytes */
while( left != 0 )
{
size_t use_len = left > md_len ? md_len : left;
@ -104,11 +116,23 @@ int hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len )
left -= use_len;
}
hmac_drbg_update( ctx, NULL, 0 );
/* 6. Update */
hmac_drbg_update( ctx, additional, add_len );
/* 7. Update reseed counter (TODO) */
/* 8. Done */
return( 0 );
}
/*
* HMAC_DRBG random function
*/
int hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len )
{
return( hmac_drbg_random_with_add( p_rng, output, out_len, NULL, 0 ) );
}
/*
* Free an HMAC_DRBG context
*/