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Implemented Gaussian rejection sampler

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The bliss_sampler class uses the mgf1_bitspender as a
pseudo-random source.
This commit is contained in:
Andreas Steffen
2014-11-29 14:51:16 +01:00
parent 72bb7eec9c
commit edd72b6bb9
6 changed files with 496 additions and 16 deletions
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src/libstrongswan/plugins/bliss/bliss_private_key.c
+90 -14
View File
@@ -15,6 +15,7 @@
#include "bliss_private_key.h"
#include "bliss_param_set.h"
#include "bliss_sampler.h"
#include "bliss_fft.h"
#include <crypto/mgf1/mgf1_bitspender.h>
@@ -82,6 +83,88 @@ METHOD(private_key_t, get_type, key_type_t,
return KEY_BLISS;
}
static bool sign_bliss_with_sha512(private_bliss_private_key_t *this,
chunk_t data, chunk_t *signature)
{
rng_t *rng;
hash_algorithm_t alg;
bliss_sampler_t *sampler;
int i, count_max = 100000000;
int hist_len = 20000, hist_len2 = hist_len / 2;
int32_t x, hist[hist_len];
double mean = 0, sigma2 = 0;
uint8_t seed_buf[32];
size_t seed_len;
chunk_t seed;
/* Set MGF1 hash algorithm and seed length based on security strength */
if (this->set->strength > 160)
{
alg = HASH_SHA256;
seed_len = HASH_SIZE_SHA256;
}
else
{
alg = HASH_SHA1;
seed_len = HASH_SIZE_SHA1;
}
seed = chunk_create(seed_buf, seed_len);
rng = lib->crypto->create_rng(lib->crypto, RNG_TRUE);
if (!rng)
{
return FALSE;
}
if (!rng->get_bytes(rng, seed_len, seed_buf))
{
rng->destroy(rng);
return FALSE;
}
rng->destroy(rng);
sampler = bliss_sampler_create(alg, seed, this->set);
if (!sampler)
{
return FALSE;
}
for (i = 0; i < hist_len; i++)
{
hist[i] = 0;
}
for (i = 0; i < count_max; i++)
{
if (!sampler->gaussian(sampler, &x))
{
sampler->destroy(sampler);
return FALSE;
}
hist[hist_len2 + x]++;
}
for (i = 0; i < hist_len; i++)
{
if (hist[i])
{
x = i - hist_len2;
DBG2(DBG_LIB, "hist[%4d] = %7u", x, hist[i]);
mean += (double)hist[i] * x;
sigma2 += (double)hist[i] * x * x;
}
}
mean /= (double)count_max;
sigma2 /= (double)count_max;
sigma2 -= mean * mean;
DBG2(DBG_LIB, "mean = %6.4f, sigma2 = %7.2f ", mean, sigma2);
sampler->destroy(sampler);
DBG2(DBG_LIB, "empty signature");
*signature = chunk_empty;
return TRUE;
}
METHOD(private_key_t, sign, bool,
private_bliss_private_key_t *this, signature_scheme_t scheme,
chunk_t data, chunk_t *signature)
@@ -89,9 +172,7 @@ METHOD(private_key_t, sign, bool,
switch (scheme)
{
case SIGN_BLISS_WITH_SHA512:
DBG2(DBG_LIB, "empty signature");
*signature = chunk_empty;
return TRUE;
return sign_bliss_with_sha512(this, data, signature);
default:
DBG1(DBG_LIB, "signature scheme %N not supported with BLISS",
signature_scheme_names, scheme);
@@ -153,7 +234,6 @@ METHOD(private_key_t, get_encoding, bool,
asn1_simple_object(ASN1_OCTET_STRING, s1_chunk),
asn1_simple_object(ASN1_OCTET_STRING, s2_chunk)
);
if (type == PRIVKEY_PEM)
{
chunk_t asn1_encoding = *encoding;
@@ -380,8 +460,7 @@ static int8_t* create_vector_from_seed(private_bliss_private_key_t *this,
non_zero = this->set->non_zero1;
while (non_zero)
{
index = bitspender->get_bits(bitspender, this->set->n_bits);
if (index == MGF1_BITSPENDER_ERROR)
if (!bitspender->get_bits(bitspender, this->set->n_bits, &index))
{
free(vector);
return NULL;
@@ -391,8 +470,7 @@ static int8_t* create_vector_from_seed(private_bliss_private_key_t *this,
continue;
}
sign = bitspender->get_bits(bitspender, 1);
if (sign == MGF1_BITSPENDER_ERROR)
if (!bitspender->get_bits(bitspender, 1, &sign))
{
free(vector);
return NULL;
@@ -404,8 +482,7 @@ static int8_t* create_vector_from_seed(private_bliss_private_key_t *this,
non_zero = this->set->non_zero2;
while (non_zero)
{
index = bitspender->get_bits(bitspender, this->set->n_bits);
if (index == MGF1_BITSPENDER_ERROR)
if (!bitspender->get_bits(bitspender, this->set->n_bits, &index))
{
free(vector);
return NULL;
@@ -415,13 +492,12 @@ static int8_t* create_vector_from_seed(private_bliss_private_key_t *this,
continue;
}
sign = bitspender->get_bits(bitspender, 1);
if (sign == MGF1_BITSPENDER_ERROR)
if (!bitspender->get_bits(bitspender, 1, &sign))
{
free(vector);
return NULL;
}
vector[index] = bitspender->get_bits(bitspender, 1) ? 2 : -2;
vector[index] = sign ? 2 : -2;
non_zero--;
}
bitspender->destroy(bitspender);
@@ -539,7 +615,7 @@ bliss_private_key_t *bliss_private_key_gen(key_type_t type, va_list args)
break;
}
/* Only BLISS-I and BLISS-IV are currently supported */
/* Only BLISS-I, BLISS-III and BLISS-IV are currently supported */
set = bliss_param_set_get_by_id(key_size);
if (!set)
{