1 files changed, 143 insertions, 0 deletions
diff --git a/lib/pubkey/nr/nr.cpp b/lib/pubkey/nr/nr.cpp
new file mode 100644
index 000000000..87cf3d038
--- /dev/null
+++ b/lib/pubkey/nr/nr.cpp
@@ -0,0 +1,143 @@
+/*
+* Nyberg-Rueppel
+* (C) 1999-2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/nr.h>
+#include <botan/numthry.h>
+#include <botan/keypair.h>
+#include <future>
+
+namespace Botan {
+
+NR_PublicKey::NR_PublicKey(const AlgorithmIdentifier& alg_id,
+                           const secure_vector<byte>& key_bits) :
+   DL_Scheme_PublicKey(alg_id, key_bits, DL_Group::ANSI_X9_57)
+   {
+   }
+
+/*
+* NR_PublicKey Constructor
+*/
+NR_PublicKey::NR_PublicKey(const DL_Group& grp, const BigInt& y1)
+   {
+   group = grp;
+   y = y1;
+   }
+
+/*
+* Create a NR private key
+*/
+NR_PrivateKey::NR_PrivateKey(RandomNumberGenerator& rng,
+                             const DL_Group& grp,
+                             const BigInt& x_arg)
+   {
+   group = grp;
+   x = x_arg;
+
+   if(x == 0)
+      x = BigInt::random_integer(rng, 2, group_q() - 1);
+
+   y = power_mod(group_g(), x, group_p());
+
+   if(x_arg == 0)
+      gen_check(rng);
+   else
+      load_check(rng);
+   }
+
+NR_PrivateKey::NR_PrivateKey(const AlgorithmIdentifier& alg_id,
+                             const secure_vector<byte>& key_bits,
+                             RandomNumberGenerator& rng) :
+   DL_Scheme_PrivateKey(alg_id, key_bits, DL_Group::ANSI_X9_57)
+   {
+   y = power_mod(group_g(), x, group_p());
+
+   load_check(rng);
+   }
+
+/*
+* Check Private Nyberg-Rueppel Parameters
+*/
+bool NR_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const
+   {
+   if(!DL_Scheme_PrivateKey::check_key(rng, strong) || x >= group_q())
+      return false;
+
+   if(!strong)
+      return true;
+
+   return KeyPair::signature_consistency_check(rng, *this, "EMSA1(SHA-1)");
+   }
+
+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())
+   {
+   }
+
+secure_vector<byte>
+NR_Signature_Operation::sign(const byte msg[], size_t msg_len,
+                             RandomNumberGenerator& rng)
+   {
+   rng.add_entropy(msg, msg_len);
+
+   BigInt f(msg, msg_len);
+
+   if(f >= q)
+      throw Invalid_Argument("NR_Signature_Operation: Input is out of range");
+
+   BigInt c, d;
+
+   while(c == 0)
+      {
+      BigInt k;
+      do
+         k.randomize(rng, q.bits());
+      while(k >= q);
+
+      c = mod_q.reduce(powermod_g_p(k) + f);
+      d = mod_q.reduce(k - x * c);
+      }
+
+   secure_vector<byte> output(2*q.bytes());
+   c.binary_encode(&output[output.size() / 2 - c.bytes()]);
+   d.binary_encode(&output[output.size() - d.bytes()]);
+   return output;
+   }
+
+NR_Verification_Operation::NR_Verification_Operation(const NR_PublicKey& nr) :
+   q(nr.group_q()), y(nr.get_y())
+   {
+   powermod_g_p = Fixed_Base_Power_Mod(nr.group_g(), nr.group_p());
+   powermod_y_p = Fixed_Base_Power_Mod(y, nr.group_p());
+   mod_p = Modular_Reducer(nr.group_p());
+   mod_q = Modular_Reducer(nr.group_q());
+   }
+
+secure_vector<byte>
+NR_Verification_Operation::verify_mr(const byte msg[], size_t msg_len)
+   {
+   const BigInt& q = mod_q.get_modulus();
+
+   if(msg_len != 2*q.bytes())
+      throw Invalid_Argument("NR verification: Invalid signature");
+
+   BigInt c(msg, q.bytes());
+   BigInt d(msg + q.bytes(), q.bytes());
+
+   if(c.is_zero() || c >= q || d >= q)
+      throw Invalid_Argument("NR verification: Invalid signature");
+
+   auto future_y_c = std::async(std::launch::async, powermod_y_p, c);
+   BigInt g_d = powermod_g_p(d);
+
+   BigInt i = mod_p.multiply(g_d, future_y_c.get());
+   return BigInt::encode_locked(mod_q.reduce(c - i));
+   }
+
+}