X25519 key exchange for TLS

Client interops with google.com, server not tested against an
independent client yet.

2 files changed, 16 insertions, 6 deletions

diff --git a/src/lib/pubkey/curve25519/curve25519.cpp b/src/lib/pubkey/curve25519/curve25519.cpp
index 02ee516de..4a072e648 100644
--- a/src/lib/pubkey/curve25519/curve25519.cpp
+++ b/src/lib/pubkey/curve25519/curve25519.cpp
@@ -29,10 +29,13 @@ secure_vector<byte> curve25519(const secure_vector<byte>& secret,
    return out;
    }
 
-secure_vector<byte> curve25519_basepoint(const secure_vector<byte>& secret)
+std::vector<byte> curve25519_basepoint(const secure_vector<byte>& secret)
    {
    const byte basepoint[32] = { 9 };
-   return curve25519(secret, basepoint);
+   std::vector<byte> out(32);
+   const int rc = curve25519_donna(out.data(), secret.data(), basepoint);
+   BOTAN_ASSERT_EQUAL(rc, 0, "Return value of curve25519_donna is ok");
+   return out;
    }
 
 }
diff --git a/src/lib/pubkey/curve25519/curve25519.h b/src/lib/pubkey/curve25519/curve25519.h
index 476db80d1..03d274e0b 100644
--- a/src/lib/pubkey/curve25519/curve25519.h
+++ b/src/lib/pubkey/curve25519/curve25519.h
@@ -27,7 +27,7 @@ class BOTAN_DLL Curve25519_PublicKey : public virtual Public_Key
 
       std::vector<byte> x509_subject_public_key() const override;
 
-      std::vector<byte> public_value() const { return unlock(m_public); }
+      std::vector<byte> public_value() const { return m_public; }
 
       /**
       * Create a Curve25519 Public Key.
@@ -39,13 +39,20 @@ class BOTAN_DLL Curve25519_PublicKey : public virtual Public_Key
 
       /**
       * Create a Curve25519 Public Key.
-      * @param pub DER encoded public key bits
+      * @param pub 32-byte raw public key
       */
-      explicit Curve25519_PublicKey(const secure_vector<byte>& pub) : m_public(pub) {}
+      explicit Curve25519_PublicKey(const std::vector<byte>& pub) : m_public(pub) {}
+
+      /**
+      * Create a Curve25519 Public Key.
+      * @param pub 32-byte raw public key
+      */
+      explicit Curve25519_PublicKey(const secure_vector<byte>& pub) :
+         m_public(pub.begin(), pub.end()) {}
 
    protected:
       Curve25519_PublicKey() {}
-      secure_vector<byte> m_public;
+      std::vector<byte> m_public;
    };
 
 class BOTAN_DLL Curve25519_PrivateKey : public Curve25519_PublicKey,