3 files changed, 152 insertions, 0 deletions
diff --git a/lib/pubkey/ecdh/ecdh.cpp b/lib/pubkey/ecdh/ecdh.cpp
new file mode 100644
index 000000000..0f93a0f97
--- /dev/null
+++ b/lib/pubkey/ecdh/ecdh.cpp
@@ -0,0 +1,35 @@
+/*
+* ECDH implemenation
+* (C) 2007 Manuel Hartl, FlexSecure GmbH
+*     2007 Falko Strenzke, FlexSecure GmbH
+*     2008-2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/ecdh.h>
+
+namespace Botan {
+
+ECDH_KA_Operation::ECDH_KA_Operation(const ECDH_PrivateKey& key) :
+   curve(key.domain().get_curve()),
+   cofactor(key.domain().get_cofactor())
+   {
+   l_times_priv = inverse_mod(cofactor, key.domain().get_order()) *
+                  key.private_value();
+   }
+
+secure_vector<byte> ECDH_KA_Operation::agree(const byte w[], size_t w_len)
+   {
+   PointGFp point = OS2ECP(w, w_len, curve);
+
+   PointGFp S = (cofactor * point) * l_times_priv;
+
+   BOTAN_ASSERT(S.on_the_curve(),
+                "ECDH agreed value was on the curve");
+
+   return BigInt::encode_1363(S.get_affine_x(),
+                              curve.get_p().bytes());
+   }
+
+}
diff --git a/lib/pubkey/ecdh/ecdh.h b/lib/pubkey/ecdh/ecdh.h
new file mode 100644
index 000000000..0c5d4e010
--- /dev/null
+++ b/lib/pubkey/ecdh/ecdh.h
@@ -0,0 +1,107 @@
+/*
+* ECDH
+* (C) 2007 Falko Strenzke, FlexSecure GmbH
+*          Manuel Hartl, FlexSecure GmbH
+* (C) 2008-2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_ECDH_KEY_H__
+#define BOTAN_ECDH_KEY_H__
+
+#include <botan/ecc_key.h>
+#include <botan/pk_ops.h>
+
+namespace Botan {
+
+/**
+* This class represents ECDH Public Keys.
+*/
+class BOTAN_DLL ECDH_PublicKey : public virtual EC_PublicKey
+   {
+   public:
+
+      ECDH_PublicKey(const AlgorithmIdentifier& alg_id,
+                     const secure_vector<byte>& key_bits) :
+         EC_PublicKey(alg_id, key_bits) {}
+
+      /**
+      * Construct a public key from a given public point.
+      * @param dom_par the domain parameters associated with this key
+      * @param public_point the public point defining this key
+      */
+      ECDH_PublicKey(const EC_Group& dom_par,
+                     const PointGFp& public_point) :
+         EC_PublicKey(dom_par, public_point) {}
+
+      /**
+      * Get this keys algorithm name.
+      * @return this keys algorithm name
+      */
+      std::string algo_name() const { return "ECDH"; }
+
+      /**
+      * Get the maximum number of bits allowed to be fed to this key.
+      * This is the bitlength of the order of the base point.
+
+      * @return maximum number of input bits
+      */
+      size_t max_input_bits() const { return domain().get_order().bits(); }
+
+      /**
+      * @return public point value
+      */
+      std::vector<byte> public_value() const
+         { return unlock(EC2OSP(public_point(), PointGFp::UNCOMPRESSED)); }
+
+   protected:
+      ECDH_PublicKey() {}
+   };
+
+/**
+* This class represents ECDH Private Keys.
+*/
+class BOTAN_DLL ECDH_PrivateKey : public ECDH_PublicKey,
+                                  public EC_PrivateKey,
+                                  public PK_Key_Agreement_Key
+   {
+   public:
+
+      ECDH_PrivateKey(const AlgorithmIdentifier& alg_id,
+                      const secure_vector<byte>& key_bits) :
+         EC_PrivateKey(alg_id, key_bits) {}
+
+      /**
+      * Generate a new private key
+      * @param rng a random number generator
+      * @param domain parameters to used for this key
+      * @param x the private key; if zero, a new random key is generated
+      */
+      ECDH_PrivateKey(RandomNumberGenerator& rng,
+                      const EC_Group& domain,
+                      const BigInt& x = 0) :
+         EC_PrivateKey(rng, domain, x) {}
+
+      std::vector<byte> public_value() const
+         { return ECDH_PublicKey::public_value(); }
+   };
+
+/**
+* ECDH operation
+*/
+class BOTAN_DLL ECDH_KA_Operation : public PK_Ops::Key_Agreement
+   {
+   public:
+      ECDH_KA_Operation(const ECDH_PrivateKey& key);
+
+      secure_vector<byte> agree(const byte w[], size_t w_len);
+   private:
+      const CurveGFp& curve;
+      const BigInt& cofactor;
+      BigInt l_times_priv;
+   };
+
+}
+
+#endif
diff --git a/lib/pubkey/ecdh/info.txt b/lib/pubkey/ecdh/info.txt
new file mode 100644
index 000000000..9277aca9b
--- /dev/null
+++ b/lib/pubkey/ecdh/info.txt
@@ -0,0 +1,10 @@
+define ECDH 20131128
+
+<requires>
+alloc
+asn1
+ec_group
+ecc_key
+libstate
+numbertheory
+</requires>