denozord/strongswan-ext
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Use mgf1_bitspender in ntru_poly_create_from_seed

Browse Source
This commit is contained in:
Andreas Steffen
2014-11-29 14:51:15 +01:00
parent 64a5cacde5
commit 8614d1214d
2 changed files with 16 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libstrongswan/plugins/ntru/ntru_poly.c
+13 -50
View File
@@ -17,7 +17,7 @@
#include "ntru_poly.h"
#include <crypto/mgf1/mgf1.h>
#include <crypto/mgf1/mgf1_bitspender.h>
#include <utils/debug.h>
#include <utils/test.h>
@@ -297,22 +297,17 @@ ntru_poly_t *ntru_poly_create_from_seed(hash_algorithm_t alg, chunk_t seed,
bool is_product_form)
{
private_ntru_poly_t *this;
size_t hash_len, octet_count = 0, i;
uint8_t octets[HASH_SIZE_SHA512], *used, num_left = 0, num_needed;
uint16_t index, limit, left = 0;
int n, num_indices, index_i = 0;
mgf1_t *mgf1;
uint32_t index, limit;
uint8_t *used;
mgf1_bitspender_t *bitspender;
DBG2(DBG_LIB, "MGF1 is seeded with %u bytes", seed.len);
mgf1 = mgf1_create(alg, seed, TRUE);
if (!mgf1)
bitspender = mgf1_bitspender_create(alg, seed, TRUE);
if (!bitspender)
{
return NULL;
}
i = hash_len = mgf1->get_hash_size(mgf1);
this = ntru_poly_create(N, q, indices_len_p, indices_len_m, is_product_form);
used = malloc(N);
limit = N * ((1 << c_bits) / N);
@@ -328,43 +323,13 @@ ntru_poly_t *ntru_poly_create_from_seed(hash_algorithm_t alg, chunk_t seed,
/* generate a random candidate index with a size of c_bits */
do
{
/* use any leftover bits first */
index = num_left ? left << (c_bits - num_left) : 0;
/* get the rest of the bits needed from new octets */
num_needed = c_bits - num_left;
while (num_needed)
index = bitspender->get_bits(bitspender, c_bits);
if (index == MGF1_BITSPENDER_ERROR)
{
if (i == hash_len)
{
/* get another block from MGF1 */
if (!mgf1->get_mask(mgf1, hash_len, octets))
{
mgf1->destroy(mgf1);
destroy(this);
free(used);
return NULL;
}
octet_count += hash_len;
i = 0;
}
left = octets[i++];
if (num_needed <= 8)
{
/* all bits needed to fill the index are in this octet */
index |= left >> (8 - num_needed);
num_left = 8 - num_needed;
num_needed = 0;
left &= 0xff >> (8 - num_left);
}
else
{
/* more than one octet will be needed */
index |= left << (num_needed - 8);
num_needed -= 8;
}
bitspender->destroy(bitspender);
destroy(this);
free(used);
return NULL;
}
}
while (index >= limit);
@@ -380,9 +345,7 @@ ntru_poly_t *ntru_poly_create_from_seed(hash_algorithm_t alg, chunk_t seed,
}
}
DBG2(DBG_LIB, "MGF1 generates %u octets to derive %u indices",
octet_count, this->num_indices);
mgf1->destroy(mgf1);
bitspender->destroy(bitspender);
free(used);
return &this->public;
src/libstrongswan/plugins/ntru/ntru_trits.c
+3 -2
View File
@@ -74,7 +74,8 @@ ntru_trits_t *ntru_trits_create(size_t len, hash_algorithm_t alg, chunk_t seed)
size_t hash_len, octet_count = 0, trits_needed, i;
mgf1_t *mgf1;
DBG2(DBG_LIB, "MGF1 is seeded with %u bytes", seed.len);
DBG2(DBG_LIB, "mgf1 based on %N is seeded with %u octets",
hash_algorithm_short_names, alg, seed.len);
mgf1 = mgf1_create(alg, seed, TRUE);
if (!mgf1)
{
@@ -122,7 +123,7 @@ ntru_trits_t *ntru_trits_create(size_t len, hash_algorithm_t alg, chunk_t seed)
}
i++;
}
DBG2(DBG_LIB, "MGF1 generates %u octets to extract %u trits",
DBG2(DBG_LIB, "mgf1 generated %u octets to extract %u trits",
octet_count, len);
mgf1->destroy(mgf1);