crypto/curve25519_unittest.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "crypto/curve25519.h"
   6
   7 #include <string>
   8
   9 #include "crypto/random.h"
  10 #include "testing/gtest/include/gtest/gtest.h"
  11
  12 namespace crypto {
  13
  14 // Test that the basic shared key exchange identity holds: that both parties end
  15 // up with the same shared key. This test starts with a fixed private key for
  16 // two parties: alice and bob. Runs ScalarBaseMult and ScalarMult to compute
  17 // public key and shared key for alice and bob. It asserts that alice and bob
  18 // have the same shared key.
  19 TEST(Curve25519, SharedKeyIdentity) {
  20   uint8 alice_private_key[curve25519::kScalarBytes] = {3};
  21   uint8 bob_private_key[curve25519::kScalarBytes] = {5};
  22
  23   // Get public key for alice and bob.
  24   uint8 alice_public_key[curve25519::kBytes];
  25   curve25519::ScalarBaseMult(alice_private_key, alice_public_key);
  26
  27   uint8 bob_public_key[curve25519::kBytes];
  28   curve25519::ScalarBaseMult(bob_private_key, bob_public_key);
  29
  30   // Get the shared key for alice, by using alice's private key and bob's
  31   // public key.
  32   uint8 alice_shared_key[curve25519::kBytes];
  33   curve25519::ScalarMult(alice_private_key, bob_public_key, alice_shared_key);
  34
  35   // Get the shared key for bob, by using bob's private key and alice's public
  36   // key.
  37   uint8 bob_shared_key[curve25519::kBytes];
  38   curve25519::ScalarMult(bob_private_key, alice_public_key, bob_shared_key);
  39
  40   // Computed shared key of alice and bob should be the same.
  41   ASSERT_EQ(0, memcmp(alice_shared_key, bob_shared_key, curve25519::kBytes));
  42 }
  43
  44 }  // namespace crypto