diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/dl_group.cpp | 15 | ||||
| -rw-r--r-- | src/dsa_gen.cpp | 77 |
2 files changed, 56 insertions, 36 deletions
diff --git a/src/dl_group.cpp b/src/dl_group.cpp index 78a2952be..9d50458dd 100644 --- a/src/dl_group.cpp +++ b/src/dl_group.cpp @@ -35,7 +35,7 @@ DL_Group::DL_Group(const std::string& type) /************************************************* * DL_Group Constructor * *************************************************/ -DL_Group::DL_Group(u32bit pbits, PrimeType type) +DL_Group::DL_Group(PrimeType type, u32bit pbits, u32bit qbits) { if(pbits < 512) throw Invalid_Argument("DL_Group: prime size " + to_string(pbits) + @@ -51,7 +51,9 @@ DL_Group::DL_Group(u32bit pbits, PrimeType type) { if(type == Prime_Subgroup) { - const u32bit qbits = 2 * dl_work_factor(pbits); + if(!qbits) + qbits = 2 * dl_work_factor(pbits); + q = random_prime(qbits); BigInt X; while(p.bits() != pbits || !is_prime(p)) @@ -61,7 +63,10 @@ DL_Group::DL_Group(u32bit pbits, PrimeType type) } } else - generate_dsa_primes(p, q, pbits); + { + qbits = qbits ? qbits : ((pbits == 1024) ? 160 : 256); + generate_dsa_primes(p, q, pbits, qbits); + } g = make_dsa_generator(p, q); } @@ -72,9 +77,9 @@ DL_Group::DL_Group(u32bit pbits, PrimeType type) /************************************************* * DL_Group Constructor * *************************************************/ -DL_Group::DL_Group(const MemoryRegion<byte>& seed, u32bit pbits, u32bit start) +DL_Group::DL_Group(const MemoryRegion<byte>& seed, u32bit pbits, u32bit qbits) { - if(!generate_dsa_primes(p, q, seed.begin(), seed.size(), pbits, start)) + if(!generate_dsa_primes(p, q, pbits, qbits, seed)) throw Invalid_Argument("DL_Group: The seed/counter given does not " "generate a DSA group"); diff --git a/src/dsa_gen.cpp b/src/dsa_gen.cpp index 996cb550e..4eecb146d 100644 --- a/src/dsa_gen.cpp +++ b/src/dsa_gen.cpp @@ -27,57 +27,71 @@ void increment(SecureVector<byte>& seed) break; } +/************************************************* +* Check if this size is allowed by FIPS 186-3 * +*************************************************/ +bool fips186_3_valid_size(u32bit pbits, u32bit qbits) + { + if(pbits == 1024 && qbits == 160) + return true; + if(pbits == 2048 && qbits == 256) + return true; + if(pbits == 3072 && qbits == 256) + return true; + return false; + } + } /************************************************* * Attempt DSA prime generation with given seed * *************************************************/ bool DL_Group::generate_dsa_primes(BigInt& p, BigInt& q, - const byte const_seed[], u32bit seed_len, - u32bit pbits, u32bit counter_start) + u32bit pbits, u32bit qbits, + const MemoryRegion<byte>& seed_c) { - if(seed_len < 20) - throw Invalid_Argument("DSA prime generation needs a seed " - "at least 160 bits long"); - if((pbits % 64 != 0) || (pbits > 1024) || (pbits < 512)) - throw Invalid_Argument("DSA prime generation algorithm does not support " - "prime size " + to_string(pbits)); + if(!fips186_3_valid_size(pbits, qbits)) + throw Invalid_Argument( + "FIPS 186-3 does not allow DSA domain parameters of " + + to_string(pbits) + "/" + to_string(qbits) + " bits long"); + + if(seed_c.size() * 8 < qbits) + throw Invalid_Argument( + "Generating a DSA parameter set with a " + to_string(qbits) + + "long q requires a seed at least as many bits long"); - std::auto_ptr<HashFunction> sha1(get_hash("SHA-1")); + std::auto_ptr<HashFunction> hash(get_hash("SHA-" + to_string(qbits))); - SecureVector<byte> seed(const_seed, seed_len); + const u32bit HASH_SIZE = hash->OUTPUT_LENGTH; - SecureVector<byte> qhash = sha1->process(seed); - increment(seed); - SecureVector<byte> qhash2 = sha1->process(seed); - xor_buf(qhash, qhash2, qhash.size()); + SecureVector<byte> seed = seed_c; + + q.binary_decode(hash->process(seed)); + q.set_bit(qbits-1); + q.set_bit(0); - qhash[0] |= 0x80; - qhash[19] |= 0x01; - q.binary_decode(qhash, qhash.size()); if(!is_prime(q)) return false; + global_state().pulse(PRIME_FOUND); - u32bit n = (pbits-1) / 160, b = (pbits-1) % 160; - SecureVector<byte> W(20 * (n+1)); - BigInt X; + const u32bit n = (pbits-1) / (HASH_SIZE * 8), b = (pbits-1) % (HASH_SIZE * 8); - for(u32bit j = 0; j != counter_start; ++j) - for(u32bit k = 0; k != n + 1; ++k) - increment(seed); + BigInt X; + SecureVector<byte> V(HASH_SIZE * (n+1)); - for(u32bit j = 0; j != 4096 - counter_start; ++j) + for(u32bit j = 0; j != 4096; ++j) { global_state().pulse(PRIME_SEARCHING); - for(u32bit k = 0; k != n + 1; ++k) + for(u32bit k = 0; k <= n; ++k) { increment(seed); - sha1->update(seed); - sha1->final(W + 20 * (n-k)); + hash->update(seed); + hash->final(V + HASH_SIZE * (n-k)); } - X.binary_decode(W + (20 - 1 - b/8), W.size() - (20 - 1 - b/8)); + + 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); @@ -95,15 +109,16 @@ bool DL_Group::generate_dsa_primes(BigInt& p, BigInt& q, * Generate DSA Primes * *************************************************/ SecureVector<byte> DL_Group::generate_dsa_primes(BigInt& p, BigInt& q, - u32bit pbits) + u32bit pbits, u32bit qbits) { - SecureVector<byte> seed(20); + SecureVector<byte> seed(qbits/8); while(true) { Global_RNG::randomize(seed, seed.size()); global_state().pulse(PRIME_SEARCHING); - if(generate_dsa_primes(p, q, seed, seed.size(), pbits, 0)) + + if(generate_dsa_primes(p, q, pbits, qbits, seed)) return seed; } } |