Move the signature padding schemes to the PK operation classes,

as was previously done with encrypt/decrypt ops.

One feature dropped on the floor here is previously PK_Signer by
default did verification of signatures before releasing them as an
measure against fault attacks. However in addition to being expensive
this turned out to be difficult to implement with the new scheme.

1 files changed, 9 insertions, 7 deletions

diff --git a/src/lib/pubkey/dsa/dsa.cpp b/src/lib/pubkey/dsa/dsa.cpp
index ca5e93f4e..90cc18fdc 100644
--- a/src/lib/pubkey/dsa/dsa.cpp
+++ b/src/lib/pubkey/dsa/dsa.cpp
@@ -74,11 +74,12 @@ namespace {
 /**
 * Object that can create a DSA signature
 */
-class DSA_Signature_Operation : public PK_Ops::Signature
+class DSA_Signature_Operation : public PK_Ops::Signature_with_EMSA
    {
    public:
       typedef DSA_PrivateKey Key_Type;
       DSA_Signature_Operation(const DSA_PrivateKey& dsa, const std::string& emsa) :
+         PK_Ops::Signature_with_EMSA(emsa),
          q(dsa.group_q()),
          x(dsa.get_x()),
          powermod_g_p(dsa.group_g(), dsa.group_p()),
@@ -91,8 +92,8 @@ class DSA_Signature_Operation : public PK_Ops::Signature
       size_t message_part_size() const override { return q.bytes(); }
       size_t max_input_bits() const override { return q.bits(); }
 
-      secure_vector<byte> sign(const byte msg[], size_t msg_len,
-                              RandomNumberGenerator& rng) override;
+      secure_vector<byte> raw_sign(const byte msg[], size_t msg_len,
+                                   RandomNumberGenerator& rng) override;
    private:
       const BigInt& q;
       const BigInt& x;
@@ -102,8 +103,8 @@ class DSA_Signature_Operation : public PK_Ops::Signature
    };
 
 secure_vector<byte>
-DSA_Signature_Operation::sign(const byte msg[], size_t msg_len,
-                              RandomNumberGenerator&)
+DSA_Signature_Operation::raw_sign(const byte msg[], size_t msg_len,
+                                  RandomNumberGenerator&)
    {
    BigInt i(msg, msg_len);
 
@@ -132,12 +133,13 @@ DSA_Signature_Operation::sign(const byte msg[], size_t msg_len,
 /**
 * Object that can verify a DSA signature
 */
-class DSA_Verification_Operation : public PK_Ops::Verification
+class DSA_Verification_Operation : public PK_Ops::Verification_with_EMSA
    {
    public:
       typedef DSA_PublicKey Key_Type;
       DSA_Verification_Operation(const DSA_PublicKey& dsa,
-                                 const std::string&) :
+                                 const std::string& emsa) :
+         PK_Ops::Verification_with_EMSA(emsa),
          q(dsa.group_q()), y(dsa.get_y())
          {
          powermod_g_p = Fixed_Base_Power_Mod(dsa.group_g(), dsa.group_p());