diff options
Diffstat (limited to 'src/lib/math/numbertheory')
| -rw-r--r-- | src/lib/math/numbertheory/dsa_gen.cpp | 18 | ||||
| -rw-r--r-- | src/lib/math/numbertheory/numthry.h | 4 |
2 files changed, 14 insertions, 8 deletions
diff --git a/src/lib/math/numbertheory/dsa_gen.cpp b/src/lib/math/numbertheory/dsa_gen.cpp index a01810025..2f952356f 100644 --- a/src/lib/math/numbertheory/dsa_gen.cpp +++ b/src/lib/math/numbertheory/dsa_gen.cpp @@ -39,7 +39,8 @@ bool fips186_3_valid_size(size_t pbits, size_t qbits) bool generate_dsa_primes(RandomNumberGenerator& rng, BigInt& p, BigInt& q, size_t pbits, size_t qbits, - const std::vector<uint8_t>& seed_c) + const std::vector<uint8_t>& seed_c, + size_t offset) { if(!fips186_3_valid_size(pbits, qbits)) throw Invalid_Argument( @@ -98,14 +99,17 @@ bool generate_dsa_primes(RandomNumberGenerator& rng, hash->final(&V[HASH_SIZE * (n-k)]); } - X.binary_decode(&V[HASH_SIZE - 1 - b/8], - V.size() - (HASH_SIZE - 1 - b/8)); - X.set_bit(pbits-1); + if(j >= offset) + { + X.binary_decode(&V[HASH_SIZE - 1 - b/8], + V.size() - (HASH_SIZE - 1 - b/8)); + X.set_bit(pbits-1); - p = X - (X % (2*q) - 1); + p = X - (X % (2*q) - 1); - if(p.bits() == pbits && is_prime(p, rng)) - return true; + if(p.bits() == pbits && is_prime(p, rng)) + return true; + } } return false; } diff --git a/src/lib/math/numbertheory/numthry.h b/src/lib/math/numbertheory/numthry.h index 6d6991c15..536dd069c 100644 --- a/src/lib/math/numbertheory/numthry.h +++ b/src/lib/math/numbertheory/numthry.h @@ -223,6 +223,7 @@ generate_dsa_primes(RandomNumberGenerator& rng, * @param pbits how long p will be in bits * @param qbits how long q will be in bits * @param seed the seed used to generate the parameters +* @param offset optional offset from seed to start searching at * @return true if seed generated a valid DSA parameter set, otherwise false. p_out and q_out are only valid if true was returned. */ @@ -230,7 +231,8 @@ bool BOTAN_DLL generate_dsa_primes(RandomNumberGenerator& rng, BigInt& p_out, BigInt& q_out, size_t pbits, size_t qbits, - const std::vector<uint8_t>& seed); + const std::vector<uint8_t>& seed, + size_t offset = 0); /** * The size of the PRIMES[] array |