Add verification ops for all signature key types

2 files changed, 62 insertions, 3 deletions

diff --git a/src/pubkey/gost_3410/gost_3410.cpp b/src/pubkey/gost_3410/gost_3410.cpp
index c3735c720..1c028eca3 100644
--- a/src/pubkey/gost_3410/gost_3410.cpp
+++ b/src/pubkey/gost_3410/gost_3410.cpp
@@ -110,9 +110,10 @@ GOST_3410_Signature_Operation::GOST_3410_Signature_Operation(
    {
    }
 
-SecureVector<byte> GOST_3410_Signature_Operation::sign(const byte msg[],
-                                                 u32bit msg_len,
-                                                 RandomNumberGenerator& rng)
+SecureVector<byte>
+GOST_3410_Signature_Operation::sign(const byte msg[],
+                                    u32bit msg_len,
+                                    RandomNumberGenerator& rng)
    {
    BigInt k;
    do
@@ -142,4 +143,39 @@ SecureVector<byte> GOST_3410_Signature_Operation::sign(const byte msg[],
    }
 
 
+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[], u32bit msg_len,
+                                              const byte sig[], u32bit sig_len)
+   {
+   if(sig_len != order.bytes()*2)
+      return false;
+
+   BigInt e(msg, msg_len);
+
+   BigInt r(sig, sig_len / 2);
+   BigInt s(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 = (z1 * base_point + z2 * public_point);
+
+   return (R.get_affine_x() == r);
+   }
+
 }
diff --git a/src/pubkey/gost_3410/gost_3410.h b/src/pubkey/gost_3410/gost_3410.h
index 12abd6354..3def2cfb9 100644
--- a/src/pubkey/gost_3410/gost_3410.h
+++ b/src/pubkey/gost_3410/gost_3410.h
@@ -113,6 +113,10 @@ class BOTAN_DLL GOST_3410_Signature_Operation : public PK_Ops::Signature_Operati
    public:
       GOST_3410_Signature_Operation(const GOST_3410_PrivateKey& gost_3410);
 
+      u32bit message_parts() const { return 2; }
+      u32bit message_part_size() const { return order.bytes(); }
+      u32bit max_input_bits() const { return order.bits(); }
+
       SecureVector<byte> sign(const byte msg[], u32bit msg_len,
                               RandomNumberGenerator& rng);
 
@@ -122,6 +126,25 @@ class BOTAN_DLL GOST_3410_Signature_Operation : public PK_Ops::Signature_Operati
       const BigInt& x;
    };
 
+class BOTAN_DLL GOST_3410_Verification_Operation : public PK_Ops::Verification
+   {
+   public:
+      GOST_3410_Verification_Operation(const GOST_3410_PublicKey& gost);
+
+      u32bit message_parts() const { return 2; }
+      u32bit message_part_size() const { return order.bytes(); }
+      u32bit max_input_bits() const { return order.bits(); }
+
+      bool with_recovery() const { return false; }
+
+      bool verify(const byte msg[], u32bit msg_len,
+                  const byte sig[], u32bit sig_len);
+   private:
+      const PointGFp& base_point;
+      const PointGFp& public_point;
+      const BigInt& order;
+   };
+
 }
 
 #endif