Curve25519-donna changes.

crypto/curve25519.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CRYPTO_CURVE25519_H
+#define CRYPTO_CURVE25519_H
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "crypto/crypto_export.h"
+
+#define crypto_scalarmult_curve25519_BYTES 32
+#define crypto_scalarmult_curve25519_SCALARBYTES 32

[wtc, 2013/03/06 00:55:58]

In a C++ header, these should be defined as enum constants
or static constants of the Curve25519 class.

[ramant (doing other things), 2013/03/06 19:01:05]

Done.

+
+namespace crypto {
+
+class CRYPTO_EXPORT Curve25519 {
+ public:
+  // ScalarMultiply computes the |shared_key| from |private_key| and
+  // |peer_public_key|. See "Computing shared secrets" section of
+  // http://cr.yp.to/ecdh.html.
+  static int ScalarMultiply(uint8* shared_key,
+                            const uint8* private_key,
+                            const uint8* peer_public_key);

[wtc, 2013/03/06 00:55:58]

This class should follow the recommendation of our Style
Guide on function parameter ordering:
  When defining a function, parameter order is: inputs, then outputs.

http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Function_Param...

You should document the meaning of the 'int' return values.
If it is used to report success/failure, use 'bool' instead.

[ramant (doing other things), 2013/03/06 19:01:05]

Made ScalarMult* methods look similar to p224's methods. It doesn't need to
return any value.

Done.

+
+  // ScalarMultiply computes the |public_key| from |private_key| and a basepoint
+  // as specified in "Computing public keys" section of
+  // http://cr.yp.to/ecdh.html.
+  static int ScalarMultiplyBase(uint8* public_key, const uint8* private_key);
+
+  // ConvertToPrivateKey returns |private_key|, generated from |mysecret|,
+  // suitable for passing to |ScalarMultiplyBase|. If |mysecret_size| is not
+  // equal to |crypto_scalarmult_curve25519_SCALARBYTES|, then it returns false
+  // and |private_key| is not updated. See "Computing secret keys" section of
+  // http://cr.yp.to/ecdh.html.
+  static bool ConvertToPrivateKey(uint8* mysecret,
+                                  size_t mysecret_size,
+                                  std::string* private_key);

[wtc, 2013/03/06 00:55:58]

This function should operate on |mysecret| in place:

  static bool ConvertToPrivateKey(uint8* mysecret,
                                  size_t mysecret_size);

I suggest shortening "mysecret" to "secret".

[ramant (doing other things), 2013/03/06 19:01:05]

Done.

+};
+
+}  // namespace crypto
+
+#endif  // CRYPTO_CURVE25519_H