1 files changed, 176 insertions, 0 deletions
diff --git a/src/lib/pubkey/gost_3410/gost_3410.cpp b/src/lib/pubkey/gost_3410/gost_3410.cpp
new file mode 100644
index 000000000..9a1e6d85b
--- /dev/null
+++ b/src/lib/pubkey/gost_3410/gost_3410.cpp
@@ -0,0 +1,176 @@
+/*
+* GOST 34.10-2001 implemenation
+* (C) 2007 Falko Strenzke, FlexSecure GmbH
+*          Manuel Hartl, FlexSecure GmbH
+* (C) 2008-2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/gost_3410.h>
+#include <botan/der_enc.h>
+#include <botan/ber_dec.h>
+
+namespace Botan {
+
+std::vector<byte> GOST_3410_PublicKey::x509_subject_public_key() const
+   {
+   // Trust CryptoPro to come up with something obnoxious
+   const BigInt x = public_point().get_affine_x();
+   const BigInt y = public_point().get_affine_y();
+
+   size_t part_size = std::max(x.bytes(), y.bytes());
+
+   std::vector<byte> bits(2*part_size);
+
+   x.binary_encode(&bits[part_size - x.bytes()]);
+   y.binary_encode(&bits[2*part_size - y.bytes()]);
+
+   // Keys are stored in little endian format (WTF)
+   for(size_t i = 0; i != part_size / 2; ++i)
+      {
+      std::swap(bits[i], bits[part_size-1-i]);
+      std::swap(bits[part_size+i], bits[2*part_size-1-i]);
+      }
+
+   return DER_Encoder().encode(bits, OCTET_STRING).get_contents_unlocked();
+   }
+
+AlgorithmIdentifier GOST_3410_PublicKey::algorithm_identifier() const
+   {
+   std::vector<byte> params =
+      DER_Encoder().start_cons(SEQUENCE)
+         .encode(OID(domain().get_oid()))
+         .end_cons()
+      .get_contents_unlocked();
+
+   return AlgorithmIdentifier(get_oid(), params);
+   }
+
+GOST_3410_PublicKey::GOST_3410_PublicKey(const AlgorithmIdentifier& alg_id,
+                                         const secure_vector<byte>& key_bits)
+   {
+   OID ecc_param_id;
+
+   // Also includes hash and cipher OIDs... brilliant design guys
+   BER_Decoder(alg_id.parameters).start_cons(SEQUENCE).decode(ecc_param_id);
+
+   domain_params = EC_Group(ecc_param_id);
+
+   secure_vector<byte> bits;
+   BER_Decoder(key_bits).decode(bits, OCTET_STRING);
+
+   const size_t part_size = bits.size() / 2;
+
+   // Keys are stored in little endian format (WTF)
+   for(size_t i = 0; i != part_size / 2; ++i)
+      {
+      std::swap(bits[i], bits[part_size-1-i]);
+      std::swap(bits[part_size+i], bits[2*part_size-1-i]);
+      }
+
+   BigInt x(&bits[0], part_size);
+   BigInt y(&bits[part_size], part_size);
+
+   public_key = PointGFp(domain().get_curve(), x, y);
+
+   BOTAN_ASSERT(public_key.on_the_curve(),
+                "Loaded GOST 34.10 public key is on the curve");
+   }
+
+namespace {
+
+BigInt decode_le(const byte msg[], size_t msg_len)
+   {
+   secure_vector<byte> msg_le(msg, msg + msg_len);
+
+   for(size_t i = 0; i != msg_le.size() / 2; ++i)
+      std::swap(msg_le[i], msg_le[msg_le.size()-1-i]);
+
+   return BigInt(&msg_le[0], msg_le.size());
+   }
+
+}
+
+GOST_3410_Signature_Operation::GOST_3410_Signature_Operation(
+   const GOST_3410_PrivateKey& gost_3410) :
+
+   base_point(gost_3410.domain().get_base_point()),
+   order(gost_3410.domain().get_order()),
+   x(gost_3410.private_value())
+   {
+   }
+
+secure_vector<byte>
+GOST_3410_Signature_Operation::sign(const byte msg[], size_t msg_len,
+                                    RandomNumberGenerator& rng)
+   {
+   BigInt k;
+   do
+      k.randomize(rng, order.bits()-1);
+   while(k >= order);
+
+   BigInt e = decode_le(msg, msg_len);
+
+   e %= order;
+   if(e == 0)
+      e = 1;
+
+   PointGFp k_times_P = base_point * k;
+
+   BOTAN_ASSERT(k_times_P.on_the_curve(),
+                "GOST 34.10 k*g is on the curve");
+
+   BigInt r = k_times_P.get_affine_x() % order;
+
+   BigInt s = (r*x + k*e) % order;
+
+   if(r == 0 || s == 0)
+      throw Invalid_State("GOST 34.10: r == 0 || s == 0");
+
+   secure_vector<byte> output(2*order.bytes());
+   s.binary_encode(&output[output.size() / 2 - s.bytes()]);
+   r.binary_encode(&output[output.size() - r.bytes()]);
+   return output;
+   }
+
+GOST_3410_Verification_Operation::GOST_3410_Verification_Operation(const GOST_3410_PublicKey& gost) :
+   base_point(gost.domain().get_base_point()),
+   public_point(gost.public_point()),
+   order(gost.domain().get_order())
+   {
+   }
+
+bool GOST_3410_Verification_Operation::verify(const byte msg[], size_t msg_len,
+                                              const byte sig[], size_t sig_len)
+   {
+   if(sig_len != order.bytes()*2)
+      return false;
+
+   BigInt e = decode_le(msg, msg_len);
+
+   BigInt s(sig, sig_len / 2);
+   BigInt r(sig + sig_len / 2, sig_len / 2);
+
+   if(r <= 0 || r >= order || s <= 0 || s >= order)
+      return false;
+
+   e %= order;
+   if(e == 0)
+      e = 1;
+
+   BigInt v = inverse_mod(e, order);
+
+   BigInt z1 = (s*v) % order;
+   BigInt z2 = (-r*v) % order;
+
+   PointGFp R = multi_exponentiate(base_point, z1,
+                                   public_point, z2);
+
+   if(R.is_zero())
+     return false;
+
+   return (R.get_affine_x() == r);
+   }
+
+}