Use mgf1_bitspender to generate random secret key

This commit is contained in:
Andreas Steffen
2014-11-29 14:51:15 +01:00
parent 988d477145
commit 64a5cacde5
@@ -17,11 +17,15 @@
#include "bliss_param_set.h"
#include "bliss_fft.h"
#include <crypto/mgf1/mgf1_bitspender.h>
#define _GNU_SOURCE
#include <stdlib.h>
typedef struct private_bliss_private_key_t private_bliss_private_key_t;
#define SECRET_KEY_TRIALS_MAX 30
/**
* Private data of a bliss_private_key_t object.
*/
@@ -155,7 +159,7 @@ static private_bliss_private_key_t *bliss_private_key_create_empty(void)
/**
* Compute the scalar product of a vector x with a negative wrapped vector y
*/
static int16_t wrapped_product(int16_t *x, int16_t *y, int n, int shift)
static int16_t wrapped_product(int8_t *x, int8_t *y, int n, int shift)
{
int16_t product = 0;
int i;
@@ -188,6 +192,9 @@ static void wrap(int16_t *x, int n, int shift, int16_t *x_wrapped)
}
}
/**
* int16_t compare function needed for qsort()
*/
static int compare(const int16_t *a, const int16_t *b)
{
int16_t temp = *a - *b;
@@ -209,7 +216,7 @@ static int compare(const int16_t *a, const int16_t *b)
/**
* Compute the Nk(S) norm of S = (s1, s2)
*/
static uint32_t nks_norm(int16_t *s1, int16_t *s2, int n, uint16_t kappa)
static uint32_t nks_norm(int8_t *s1, int8_t *s2, int n, uint16_t kappa)
{
int16_t t[n], t_wrapped[n], max_kappa[n];
uint32_t nks = 0;
@@ -271,6 +278,158 @@ static uint32_t invert(uint32_t x, uint16_t q)
return x1;
}
/**
* Create a vector with sparse and small coefficients from seed
*/
static int8_t* create_vector_from_seed(private_bliss_private_key_t *this,
hash_algorithm_t alg, chunk_t seed)
{
mgf1_bitspender_t *bitspender;
uint32_t index, sign;
int8_t *vector;
int non_zero;
bitspender = mgf1_bitspender_create(alg, seed, FALSE);
if (!bitspender)
{
return NULL;
}
vector = malloc(sizeof(int8_t) * this->set->n);
memset(vector, 0x00, this->set->n);
non_zero = this->set->non_zero1;
while (non_zero)
{
index = bitspender->get_bits(bitspender, this->set->n_bits);
if (index == MGF1_BITSPENDER_ERROR)
{
free(vector);
return NULL;
}
if (vector[index] != 0)
{
continue;
}
sign = bitspender->get_bits(bitspender, 1);
if (sign == MGF1_BITSPENDER_ERROR)
{
free(vector);
return NULL;
}
vector[index] = sign ? 1 : -1;
non_zero--;
}
non_zero = this->set->non_zero2;
while (non_zero)
{
index = bitspender->get_bits(bitspender, this->set->n_bits);
if (index == MGF1_BITSPENDER_ERROR)
{
free(vector);
return NULL;
}
if (vector[index] != 0)
{
continue;
}
sign = bitspender->get_bits(bitspender, 1);
if (sign == MGF1_BITSPENDER_ERROR)
{
free(vector);
return NULL;
}
vector[index] = bitspender->get_bits(bitspender, 1) ? 2 : -2;
non_zero--;
}
bitspender->destroy(bitspender);
return vector;
}
/**
* Generate the secret key S = (s1, s2) fulfilling the Nk(S) norm
*/
static bool create_secret(private_bliss_private_key_t *this, rng_t *rng,
int8_t **s1, int8_t **s2, int *trials)
{
uint8_t seed_buf[32];
uint8_t *f, *g;
uint32_t l2_norm, nks;
int i, n;
chunk_t seed;
size_t seed_len;
hash_algorithm_t alg;
n = this->set->n;
*s1 = NULL;
*s2 = NULL;
/* 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);
while (*trials < SECRET_KEY_TRIALS_MAX)
{
(*trials)++;
if (!rng->get_bytes(rng, seed_len, seed_buf))
{
return FALSE;
}
f = create_vector_from_seed(this, alg, seed);
if (f == NULL)
{
return FALSE;
}
if (!rng->get_bytes(rng, seed_len, seed_buf))
{
free(f);
return FALSE;
}
g = create_vector_from_seed(this, alg, seed);
if (g == NULL)
{
free(f);
return FALSE;
}
/* Compute 2g + 1 */
for (i = 0; i < n; i++)
{
g[i] *= 2;
}
g[0] += 1;
l2_norm = wrapped_product(f, f, n, 0) + wrapped_product(g, g, n, 0);
nks = nks_norm(f, g, n, this->set->kappa);
DBG2(DBG_LIB, "l2 norm of s1||s2: %d, Nk(S): %u (%u max)",
l2_norm, nks, this->set->nks_max);
if (nks < this->set->nks_max)
{
*s1 = f;
*s2 = g;
return TRUE;
}
free(f);
free(g);
}
return FALSE;
}
/**
* See header.
*/
@@ -278,250 +437,14 @@ bliss_private_key_t *bliss_private_key_gen(key_type_t type, va_list args)
{
private_bliss_private_key_t *this;
u_int key_size = 1;
int i;
uint32_t *a, *A, *F, *G, nks;
uint16_t q, n, l2_norm;
int i, n, trials = 0;
int8_t *s1 = NULL, *s2 = NULL;
uint16_t q;
uint32_t *a, *A, *S1, *S2;
bool success = FALSE;
bliss_param_set_t *set;
bliss_fft_t *fft;
int16_t f_bliss1[] = {
0, 0, 0, 0, 1, 1, 0, -1, 0, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, -1, 0, 0, 0, -1, 1, 0, 0,
1, 1, -1, 0, 1, 1, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, -1, 0, -1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-1, 0, 1, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 1, 0, -1, 0, 0,
0, -1, 0, 0, 1, -1, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 1, 0, -1, 0, 1,
1, -1, 0, 1, 0, 1, 0, 0, 1, 0,
-1, 0, 0, 0, 1, -1, 1, 0, 1, 0,
0, 0, 0, -1, -1, 0, 0, 0, -1, 0,
-1, 0, 0, 0, 1, 0, 1, 0, 0, 1,
0, -1, 0, 0, 0, -1, 0, -1, 0, 0,
-1, 0, 0, -1, 1, 1, -1, 0, 0, -1,
0, 0, 1, -1, 0, -1, 0, 0, 1, 0,
0, 1, 1, 0, 0, 0, -1, 0, 0, -1,
0, 0, 0, -1, 1, 0, 0, -1, 0, 1,
0, 0, 1, -1, -1, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, 0, 0, -1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, -1, 0, 0, 0, 0, 0, 1, 0,
0, 1, 0, 1, 0, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 1, 0, 0, -1, 0,
1, -1, 0, 0, 0, 0, 1, 0, -1, 0,
-1, 0, -1, 1, 0, 0, 1, 1, 0, 0,
0, 0, 0, 0, 0, 1, 0, 0, -1, 0,
0, 1, -1, 0, 1, 0, 0, 0, 1, -1,
-1, 0, 0, 0, -1, 0, 1, 0, 0, 0,
0, 0, 1, -1, 1, 0, 0, 0, 0, 0,
0, -1, 0, 1, 0, 0, 0, 0, 0, -1,
0, 0, 0, 0, 0, 0, 0, 1, 0, 1,
0, 0, 0, 0, -1, 1, 0, 0, 0, 0,
0, 0, 0, 0, -1, 0, 0, 0, 0, 1,
0, -1, 0, 0, 0, 1, 0, 1, -1, 1,
0, 0, 0, 0, 1, 1, 0, 1, 0, 0,
0, -1, 1, 0, 1, -1, 0, 0, -1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, -1, 0,
0, -1, 0, 0, 0, 1, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, 0, -1, 0, 0,
0, 0, -1, 1, 0, 1, 0, 0, -1, 0,
0, -1, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-1, 0, 0, 1, 0, -1, 1, 0, 1, 0,
-1, 1, 0, 0, 0, 0, 0, 0, 0, -1,
0, 0, 0, 0, 0, 1, 1, 0, -1, 0,
-1, 0, 0, 0, -1, -1, 0, 0, 0, 0,
0, 0, -1, -1, 0, 1, -1, 0, 0, 0,
0, -1
};
int16_t g_bliss1[] = {
-1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 1, 1, 0,
1, 0, 0, 0, 1, 0, -1, 0, 0, 0,
0, 0, 0, 0, -1, 1, 0, 0, 0, 0,
0, 0, -1, 1, 0, 0, 0, 0, 0, -1,
-1, 0, -1, 0, 1, -1, 0, 0, 0, 0,
0, 0, 0, 0, 1, -1, 0, 0, 1, 0,
0, 1, 0, -1, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, -1, 1, 0, -1, 0, 1,
0, 1, 0, 0, 1, 0, -1, 1, 0, 0,
0, 0, 0, 0, 0, 0, 1, 1, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 1, 0, 0, 1,
1, 1, 1, 0, 0, 0, 0, 0, -1, 0,
1, 1, 0, 0, 1, 0, -1, 1, 0, 0,
-1, 0, 0, -1, 0, 0, 0, 0, 0, 0,
0, 0, 0, -1, 0, -1, 1, 0, 0, -1,
0, 0, -1, 0, 0, 0, 0, 0, 0, -1,
0, 0, 1, 0, 0, 0, 0, -1, 0, 1,
0, 0, -1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 1, 0, 1,
1, 0, -1, 0, 0, 0, 0, 1, 1, 0,
0, -1, 1, 1, 0, 0, 0, -1, 1, 0,
0, 1, 0, 0, 0, 0, -1, 1, 0, 0,
-1, 0, 1, 0, 0, 0, -1, -1, 0, 0,
0, -1, 1, 1, 0, 1, 0, 0, 0, 0,
0, 0, 1, 0, 0, 1, 1, 1, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 1,
0, -1, -1, 0, -1, 0, -1, -1, 1, -1,
-1, 0, 0, 0, -1, 0, 0, 0, 0, 0,
-1, 1, 0, -1, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, -1, 0, 0, -1,
1, 0, 0, -1, 0, 0, 0, 0, 0, -1,
0, 0, -1, 0, 0, 0, -1, 0, 0, 0,
0, 0, 0, 1, 1, 0, 0, 0, 0, 0,
-1, 0, 0, 0, 0, 0, -1, 0, 0, 0,
1, 1, 1, 0, 0, 0, 0, -1, -1, 0,
-1, 0, 1, 0, 0, 0, 0, 0, -1, 0,
-1, 0, 0, 0, 0, 1, 0, 0, -1, -1,
1, 0, 0, 0, 0, 0, 0, 0, -1, 0,
0, 0, 1, -1, 0, 0, 1, 0, 0, 1,
-1, 0, 1, 0, 1, 1, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, -1, 0, 0, 0, 0, 1, 1, 0, 0,
1, 0, -1, 0, 0, 1, 1, 0, 0, 0,
0, 0, -1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, -1, -1, 0, 0, 0, 0, 1,
-1, -1, 1, 0, 0, 0, 0, 0, 0, 1,
0, 0, 0, 1, 0, 0, 0, 1, 1, 0,
-1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, -1
};
int16_t f[] = {
0, -1, -1, 0, 0, 1, -1, -1, 0, 0,
0, 0, 1, 1, 0, 0, 0, 1, -1, 1,
-2, 1, 0, 0, -1, 0, 0, 0, -1, 0,
0, -1, 0, 1, 1, -1, 0, 1, -2, -1,
1, 0, 0, 0, 0, -1, -1, 0, 1, 2,
0, 0, 1, 0, -1, 0, 1, 1, 1, 0,
2, -1, 0, 0, 1, 0, 0, -1, 0, 0,
0, 0, 1, 0, 0, -1, 0, -1, -1, 0,
0, 0, 0, -1, -2, -1, -1, -1, 1, 0,
0, 1, 0, 1, -1, -1, 0, 0, 0, 1,
0, -1, 1, 1, 1, 0, -1, 0, 0, -1,
0, 1, -1, 1, -2, 0, 1, 1, -1, 0,
1, -1, -2, 0, 0, -1, 0, 0, 1, 0,
0, 0, 1, -1, 1, -2, 0, 0, -1, 1,
0, 0, -1, -1, 0, -1, 0, 0, 0, 0,
-1, 0, 1, -1, 1, 0, -1, 1, 0, 1,
1, 0, 0, -1, 0, 1, 1, 0, -1, 1,
1, 1, 2, 0, 0, 1, 0, 1, 0, 0,
-1, -1, 0, -2, 0, -1, 0, 0, -1, 1,
-1, -2, 0, 2, 0, -1, 2, 1, 0, 1,
1, 1, 1, 0, -1, 1, -1, 1, 1, -1,
0, 1, 1, 1, 0, 0, 0, 0, 1, 0,
-2, 0, 1, 1, 0, -1, -1, 1, 0, 1,
-2, 1, 1, -1, 1, 0, 0, 1, -1, -1,
1, 0, 1, 1, 1, -1, 0, -1, 0, 0,
0, 0, 1, 0, 0, -1, 0, 0, 0, 0,
1, -1, 2, -1, 1, 0, 0, 1, 0, 0,
0, -1, -1, 2, 1, 1, 0, -1, 0, -1,
0, 0, 0, 0, 0, 0, 0, -1, -1, 0,
0, 0, 0, -1, 0, 1, 1, 1, -1, 0,
-1, 1, 0, 1, 0, 0, 0, 1, 0, -1,
0, 0, 1, -2, 0, 0, 0, 0, -1, 1,
0, 1, 0, 0, 0, -1, 0, 1, 0, -1,
0, 1, -1, 0, 0, 1, 0, 0, 0, 0,
1, -1, 0, -2, 0, 0, 2, 0, -1, -1,
-1, 1, 1, 0, 1, -1, 1, 2, -1, 1,
-1, 0, 1, -2, 0, 0, -1, 2, -1, 0,
-1, 0, -1, 0, 1, -2, 0, 2, 0, 0,
1, -1, 1, -1, 1, 0, 1, 1, -1, 0,
0, 0, -1, -1, 0, 0, 0, -1, -2, 0,
0, 0, 1, -2, 0, 0, 1, 1, 0, -1,
0, 0, 0, 0, 0, 1, 0, 0, 0, 0,
0, 0, -1, 0, 0, 0, 1, 0, 0, 0,
1, 2, 0, -1, 0, 0, 1, 0, 0, 0,
-1, 0, 0, 1, -1, 0, -1, 0, 0, -1,
-1, -1, 2, 0, 0, 0, -1, 0, 2, 0,
-1, 0, -1, 0, -1, 1, 0, 0, 0, 0,
-1, 2, 0, 1, 0, 0, -1, 0, 0, 0,
1, -1, -1, 0, 0, -1, 0, -1, 1, -1,
1, 0, -1, -1, 1, 1, 0, 0, 0, 0,
0, 0, 0, 1, -1, 0, 0, 0, 0, 0,
0, 0
};
int16_t g[] = {
0, 2, 1, 0, -1, 1, 1, 1, -1, -1,
1, 2, 0, 0, 0, -1, 0, -1, 1, 0,
1, -1, 1, 0, 0, 0, -1, -1, 1, 0,
-1, 1, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, -1, -1, -1, -1, 0, 0, 0, 0,
0, -1, 0, -1, -2, 0, 0, 1, 0, -1,
-1, -1, -1, -1, 2, 1, -1, 0, -1, 0,
0, 1, 1, 0, 1, 0, 0, 0, -1, 1,
0, 1, 0, 0, 0, 1, 0, 0, 0, 0,
0, -1, 0, 0, 0, -1, 0, 0, 0, 0,
0, 1, -2, 1, 1, -1, 1, 1, 0, 1,
0, 0, 1, 0, 0, 0, -1, 0, 0, 0,
0, 0, 1, 0, 1, -1, 0, 0, 0, 1,
1, 1, 0, 0, 1, 0, 0, 1, 1, 1,
0, 0, 0, -1, 0, -1, -2, 1, 0, 1,
0, -1, -2, 1, 0, 0, -1, 0, 0, 0,
0, 0, 1, 0, 1, -1, 1, 1, -1, 0,
0, 0, 1, -1, 1, 1, -2, -1, 1, 0,
-2, 0, 0, 0, 1, 1, 2, 0, 2, 1,
1, 0, 1, 0, -1, 1, 0, 0, 0, -1,
-1, -1, 0, 0, -1, 1, 0, 1, 0, -1,
0, 0, 2, 1, 0, 0, 1, -2, -1, 0,
1, 0, -1, 1, -1, 0, 1, -1, -1, 1,
0, 0, -1, -1, -1, 0, 0, 1, -2, -1,
0, -1, 1, -1, 1, -1, 0, -1, -1, 1,
0, 1, -1, 0, 2, 1, -1, 0, -2, 0,
-1, 0, 0, 1, 0, -1, 1, 1, 0, 0,
0, -1, -2, 1, 0, 0, 2, 0, -1, 0,
1, 1, 0, -1, 0, 0, -1, -1, -1, 0,
0, -1, 0, 0, 0, 0, 1, 0, -1, -1,
1, -1, 0, 0, 1, 0, -1, 1, 0, 1,
0, 1, 1, 1, -1, 0, 0, 1, 0, -1,
0, -1, 0, 0, 0, -1, -1, 0, 0, 0,
-1, -1, 0, 1, 0, 0, 0, 1, 0, 0,
1, 1, -1, 0, 0, 0, -1, 0, 1, 1,
0, 1, 0, 1, 0, -1, -1, 0, 0, 0,
2, -1, 0, 0, -1, 1, -1, -2, -1, 0,
0, 1, 0, 1, 1, 0, 0, 0, -1, 2,
0, -1, 0, 0, 0, -1, -1, -1, 0, 1,
-2, 0, 0, 1, -1, 0, 0, 0, 1, 1,
1, 1, 0, -1, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, -2, 0, 0, 0,
2, 1, 0, 0, 0, 0, 1, 0, 0, -1,
1, -2, 0, 0, 1, 1, 1, 0, -2, 0,
-1, 0, 1, 2, 1, 0, 0, -2, 0, -1,
-1, 0, 1, 0, 1, 0, 1, 0, -1, -1,
2, 0, 1, -1, 0, 1, 0, 0, 0, -1,
1, 0, 1, -1, 0, 0, 0, 0, 0, -1,
0, 0, 1, -1, 0, 0, 1, 1, 0, 0,
0, 1, -1, 0, -1, -2, -1, 0, 0, -2,
0, -1, 0, 0, 0, -1, 1, 0, 1, 1,
-1, 0
};
rng_t *rng;
while (TRUE)
{
@@ -538,7 +461,7 @@ int16_t g[] = {
break;
}
/* Only BLISS-I and BLISS-IV are supported */
/* Only BLISS-I and BLISS-IV are currently supported */
set = bliss_param_set_get_by_id(key_size);
if (!set)
{
@@ -561,58 +484,81 @@ int16_t g[] = {
/* We derive the public key from the private key using the FFT */
fft = bliss_fft_create(set->fft_params);
/* Compute 2g + 1 */
for (i = 0; i < n; i++)
/* Some vectors needed to derive the publi key */
S1 = malloc(n * sizeof(uint32_t));
S2 = malloc(n * sizeof(uint32_t));
A = malloc(n * sizeof(uint32_t));
a = malloc(n * sizeof(uint32_t));
/* Instantiate a true random generator */
rng = lib->crypto->create_rng(lib->crypto, RNG_TRUE);
/* Loop until we have an invertible polynomial s1 */
do
{
g[i] *= 2;
}
g[0] += 1;
l2_norm = wrapped_product(f, f, n, 0) + wrapped_product(g, g, n, 0);
nks = nks_norm(f, g, n, set->kappa);
DBG2(DBG_LIB, "L2 norm of s1||s2: %d, Nk(S): %u (%u max)",
l2_norm, nks, set->nks_max);
F = malloc(n * sizeof(uint32_t));
G = malloc(n * sizeof(uint32_t));
A = malloc(n * sizeof(uint32_t));
a = malloc(n * sizeof(uint32_t));
/* Convert signed arrays to unsigned arrays before FFT */
for (i = 0; i < n; i++)
{
F[i] = (f[i] < 0) ? f[i] + q : f[i];
G[i] = (g[i] < 0) ? g[i] + q : g[i];
}
fft->transform(fft, F, F, FALSE);
fft->transform(fft, G, G, FALSE);
for (i = 0; i < n; i++)
{
if (F[i] == 0)
if (!create_secret(this, rng, &s1, &s2, &trials))
{
DBG1(DBG_LIB, "F[%d] is zero", i);
break;
}
A[i] = invert(F[i], q);
A[i] = (G[i] * A[i]) % q;
}
fft->transform(fft, A, a, TRUE);
DBG4(DBG_LIB, " i f g a F G A");
for (i = 0; i < n; i++)
/* Convert signed arrays to unsigned arrays before FFT */
for (i = 0; i < n; i++)
{
S1[i] = (s1[i] < 0) ? s1[i] + q : s1[i];
S1[i] = (s2[i] < 0) ? s2[i] + q : s2[i];
}
fft->transform(fft, S1, S1, FALSE);
fft->transform(fft, S2, S2, FALSE);
success = TRUE;
for (i = 0; i < n; i++)
{
if (S1[i] == 0)
{
DBG1(DBG_LIB, "S1[%d] is zero - s1 is not invertible", i);
free(s1);
s1 = NULL;
free(s2);
s2 = NULL;
success = FALSE;
break;
}
A[i] = invert(S1[i], q);
A[i] = (S2[i] * A[i]) % q;
}
}
while (!success && trials < SECRET_KEY_TRIALS_MAX);
DBG1(DBG_LIB, "secret key generation %s after %d trial%s",
success ? "succeeded" : "failed", trials, (trials == 1) ? "" : "s");
if (success)
{
DBG4(DBG_LIB, "%4d %3d %3d %5u %5u %5u %5u",
i, f[i], g[i], a[i], F[i], G[i], A[i]);
fft->transform(fft, A, a, TRUE);
DBG4(DBG_LIB, " i f g a F G A");
for (i = 0; i < n; i++)
{
DBG4(DBG_LIB, "%4d %3d %3d %5u %5u %5u %5u",
i, s1[i], s2[i], a[i], S1[i], S2[i], A[i]);
}
}
else
{
destroy(this);
}
/* Cleanup */
fft->destroy(fft);
rng->destroy(rng);
free(s1);
free(s2);
free(a);
free(A);
free(F);
free(G);
free(S1);
free(S2);
return &this->public;
return success ? &this->public : NULL;
}
/**