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Allow SHA256 and SHA384 data hash for BLISS signatures.

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The default is SHA512 since this hash function is also
used for the c_indices random oracle.
This commit is contained in:
Andreas Steffen
2015-02-26 08:56:12 +01:00
parent a7f0ab786d
commit 27bd0fed93
17 changed files with 133 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libstrongswan/plugins/bliss/bliss_private_key.c
+32 -19
View File
@@ -158,18 +158,20 @@ static void greedy_sc(int8_t *s1, int8_t *s2, int n, uint16_t *c_indices,
}
/**
* Compute a BLISS signature based on a SHA-512 hash
* Compute a BLISS signature
*/
static bool sign_bliss_with_sha512(private_bliss_private_key_t *this,
chunk_t data, chunk_t *signature)
static bool sign_bliss(private_bliss_private_key_t *this, hash_algorithm_t alg,
chunk_t data, chunk_t *signature)
{
rng_t *rng;
hash_algorithm_t alg;
hasher_t *hasher;
bliss_fft_t *fft;
bliss_signature_t *sig;
bliss_sampler_t *sampler = NULL;
uint8_t seed_buf[32], data_hash_buf[HASH_SIZE_SHA512];
rng_t *rng;
hasher_t *hasher;
hash_algorithm_t mgf1_alg;
size_t mgf1_seed_len;
uint8_t mgf1_seed_buf[HASH_SIZE_SHA512], data_hash_buf[HASH_SIZE_SHA512];
chunk_t mgf1_seed, data_hash;
uint16_t q, q2, p, p2, *c_indices, tests = 0;
uint32_t *ay;
int32_t *y1, *y2, *z1, *z2, *u, *s1c, *s2c;
@@ -177,39 +179,46 @@ static bool sign_bliss_with_sha512(private_bliss_private_key_t *this,
int32_t scalar, norm, ui;
int16_t *ud, *uz2d, *z2d, value;
int i, n;
size_t seed_len;
double mean1 = 0, mean2 = 0, sigma1 = 0, sigma2 = 0;
chunk_t seed;
chunk_t data_hash = { data_hash_buf, sizeof(data_hash_buf) };
bool accepted, positive, success = FALSE, use_bliss_b;
/* Initialize signature */
*signature = chunk_empty;
/* Create data hash */
hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA512);
hasher = lib->crypto->create_hasher(lib->crypto, alg);
if (!hasher)
{
return FALSE;
}
data_hash = chunk_create(data_hash_buf, hasher->get_hash_size(hasher));
if (!hasher->get_hash(hasher, data, data_hash_buf))
{
hasher->destroy(hasher);
return FALSE;
}
hasher->destroy(hasher);
/* Create SHA512 hasher for c_indices oracle */
hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA512);
if (!hasher)
{
return FALSE;
}
/* Set MGF1 hash algorithm and seed length based on security strength */
if (this->set->strength > 160)
{
alg = HASH_SHA256;
seed_len = HASH_SIZE_SHA256;
mgf1_alg = HASH_SHA256;
mgf1_seed_len = HASH_SIZE_SHA256;
}
else
{
alg = HASH_SHA1;
seed_len = HASH_SIZE_SHA1;
mgf1_alg = HASH_SHA1;
mgf1_seed_len = HASH_SIZE_SHA1;
}
seed = chunk_create(seed_buf, seed_len);
mgf1_seed = chunk_create(mgf1_seed_buf, mgf1_seed_len);
rng = lib->crypto->create_rng(lib->crypto, RNG_STRONG);
if (!rng)
@@ -260,13 +269,13 @@ static bool sign_bliss_with_sha512(private_bliss_private_key_t *this,
{
tests++;
if (!rng->get_bytes(rng, seed_len, seed_buf))
if (!rng->get_bytes(rng, mgf1_seed_len, mgf1_seed_buf))
{
goto end;
}
DESTROY_IF(sampler);
sampler = bliss_sampler_create(alg, seed, this->set);
sampler = bliss_sampler_create(mgf1_alg, mgf1_seed, this->set);
if (!sampler)
{
goto end;
@@ -507,8 +516,12 @@ METHOD(private_key_t, sign, bool,
{
switch (scheme)
{
case SIGN_BLISS_WITH_SHA256:
return sign_bliss(this, HASH_SHA256, data, signature);
case SIGN_BLISS_WITH_SHA384:
return sign_bliss(this, HASH_SHA384, data, signature);
case SIGN_BLISS_WITH_SHA512:
return sign_bliss_with_sha512(this, data, signature);
return sign_bliss(this, HASH_SHA512, data, signature);
default:
DBG1(DBG_LIB, "signature scheme %N not supported with BLISS",
signature_scheme_names, scheme);