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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*/
#include "tomcrypt.h"
/**
@file sprng.c
Secure PRNG, Tom St Denis
*/
/* A secure PRNG using the RNG functions. Basically this is a
* wrapper that allows you to use a secure RNG as a PRNG
* in the various other functions.
*/
#ifdef LTC_SPRNG
const struct ltc_prng_descriptor sprng_desc =
{
"sprng", 0,
&sprng_start,
&sprng_add_entropy,
&sprng_ready,
&sprng_read,
&sprng_done,
&sprng_export,
&sprng_import,
&sprng_test
};
/**
Start the PRNG
@param prng [out] The PRNG state to initialize
@return CRYPT_OK if successful
*/
int sprng_start(prng_state *prng)
{
LTC_UNUSED_PARAM(prng);
return CRYPT_OK;
}
/**
Add entropy to the PRNG state
@param in The data to add
@param inlen Length of the data to add
@param prng PRNG state to update
@return CRYPT_OK if successful
*/
int sprng_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng)
{
LTC_UNUSED_PARAM(in);
LTC_UNUSED_PARAM(inlen);
LTC_UNUSED_PARAM(prng);
return CRYPT_OK;
}
/**
Make the PRNG ready to read from
@param prng The PRNG to make active
@return CRYPT_OK if successful
*/
int sprng_ready(prng_state *prng)
{
LTC_UNUSED_PARAM(prng);
return CRYPT_OK;
}
/**
Read from the PRNG
@param out Destination
@param outlen Length of output
@param prng The active PRNG to read from
@return Number of octets read
*/
unsigned long sprng_read(unsigned char *out, unsigned long outlen, prng_state *prng)
{
LTC_ARGCHK(out != NULL);
LTC_UNUSED_PARAM(prng);
return rng_get_bytes(out, outlen, NULL);
}
/**
Terminate the PRNG
@param prng The PRNG to terminate
@return CRYPT_OK if successful
*/
int sprng_done(prng_state *prng)
{
LTC_UNUSED_PARAM(prng);
return CRYPT_OK;
}
/**
Export the PRNG state
@param out [out] Destination
@param outlen [in/out] Max size and resulting size of the state
@param prng The PRNG to export
@return CRYPT_OK if successful
*/
int sprng_export(unsigned char *out, unsigned long *outlen, prng_state *prng)
{
LTC_ARGCHK(outlen != NULL);
LTC_UNUSED_PARAM(out);
LTC_UNUSED_PARAM(prng);
*outlen = 0;
return CRYPT_OK;
}
/**
Import a PRNG state
@param in The PRNG state
@param inlen Size of the state
@param prng The PRNG to import
@return CRYPT_OK if successful
*/
int sprng_import(const unsigned char *in, unsigned long inlen, prng_state *prng)
{
LTC_UNUSED_PARAM(in);
LTC_UNUSED_PARAM(inlen);
LTC_UNUSED_PARAM(prng);
return CRYPT_OK;
}
/**
PRNG self-test
@return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled
*/
int sprng_test(void)
{
#ifndef LTC_TEST
return CRYPT_NOP;
#else
prng_state st;
unsigned char en[] = { 0x01, 0x02, 0x03, 0x04 };
unsigned char out[1000];
int err;
if ((err = sprng_start(&st)) != CRYPT_OK) return err;
if ((err = sprng_add_entropy(en, sizeof(en), &st)) != CRYPT_OK) return err;
if ((err = sprng_ready(&st)) != CRYPT_OK) return err;
if (sprng_read(out, 500, &st) != 500) return CRYPT_ERROR_READPRNG; /* skip 500 bytes */
if ((err = sprng_done(&st)) != CRYPT_OK) return err;
return CRYPT_OK;
#endif
}
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
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