Add signature generation operation classes. Remove sign() from

PK_Signing_Key, though for the moment the class remains because there
are a few pieces of code that use it to detect if signatures are
supported, or for passing to functions in look_pk

2 files changed, 57 insertions, 3 deletions

diff --git a/src/pubkey/nr/nr.cpp b/src/pubkey/nr/nr.cpp
index cdcaf3af3..08ed6b376 100644
--- a/src/pubkey/nr/nr.cpp
+++ b/src/pubkey/nr/nr.cpp
@@ -1,6 +1,6 @@
 /*
 * Nyberg-Rueppel
-* (C) 1999-2007 Jack Lloyd
+* (C) 1999-2010 Jack Lloyd
 *
 * Distributed under the terms of the Botan license
 */
@@ -115,4 +115,39 @@ bool NR_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const
    return true;
    }
 
+NR_Signature_Operation::NR_Signature_Operation(const NR_PrivateKey& nr) :
+   q(nr.group_q()),
+   x(nr.get_x()),
+   powermod_g_p(nr.group_g(), nr.group_p()),
+   mod_q(nr.group_q())
+   {
+   }
+
+SecureVector<byte> NR_Signature_Operation::sign(const byte msg[],
+                                                u32bit msg_len,
+                                                RandomNumberGenerator& rng)
+   {
+   rng.add_entropy(msg, msg_len);
+
+   BigInt k;
+   do
+      k.randomize(rng, q.bits());
+   while(k >= q);
+
+   BigInt f(msg, msg_len);
+
+   if(f >= q)
+      throw Invalid_Argument("NR_Signature_Operation: Input is out of range");
+
+   BigInt c = mod_q.reduce(powermod_g_p(k) + f);
+   if(c.is_zero())
+      throw Internal_Error("Default_NR_Op::sign: c was zero");
+   BigInt d = mod_q.reduce(k - x * c);
+
+   SecureVector<byte> output(2*q.bytes());
+   c.binary_encode(output + (output.size() / 2 - c.bytes()));
+   d.binary_encode(output + (output.size() - d.bytes()));
+   return output;
+   }
+
 }
diff --git a/src/pubkey/nr/nr.h b/src/pubkey/nr/nr.h
index 1479ef064..013f3d42b 100644
--- a/src/pubkey/nr/nr.h
+++ b/src/pubkey/nr/nr.h
@@ -9,6 +9,7 @@
 #define BOTAN_NYBERG_RUEPPEL_H__
 
 #include <botan/dl_algo.h>
+#include <botan/pk_ops.h>
 #include <botan/nr_core.h>
 
 namespace Botan {
@@ -24,11 +25,11 @@ class BOTAN_DLL NR_PublicKey : public PK_Verifying_with_MR_Key,
 
       SecureVector<byte> verify(const byte sig[], u32bit sig_len) const;
 
-      u32bit max_input_bits() const { return (group_q().bits() - 1); }
-
       DL_Group::Format group_format() const { return DL_Group::ANSI_X9_57; }
+
       u32bit message_parts() const { return 2; }
       u32bit message_part_size() const { return group_q().bytes(); }
+      u32bit max_input_bits() const { return (group_q().bits() - 1); }
 
       NR_PublicKey(const AlgorithmIdentifier& alg_id,
                    const MemoryRegion<byte>& key_bits);
@@ -61,6 +62,24 @@ class BOTAN_DLL NR_PrivateKey : public NR_PublicKey,
                     const BigInt& x = 0);
    };
 
+class BOTAN_DLL NR_Signature_Operation : public PK_Ops::Signature_Operation
+   {
+   public:
+      NR_Signature_Operation(const NR_PrivateKey& nr);
+
+      u32bit message_parts() const { return 2; }
+      u32bit message_part_size() const { return q.bytes(); }
+      u32bit max_input_bits() const { return (q.bits() - 1); }
+
+      SecureVector<byte> sign(const byte msg[], u32bit msg_len,
+                              RandomNumberGenerator& rng);
+   private:
+      const BigInt& q;
+      const BigInt& x;
+      Fixed_Base_Power_Mod powermod_g_p;
+      Modular_Reducer mod_q;
+   };
+
 }
 
 #endif