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// Copyright 2015 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.
#include "components/gcm_driver/crypto/p256_key_util.h"
#include <stddef.h>
#include <set>
#include "base/base64.h"
#include "crypto/ec_private_key.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace gcm {
namespace {
// A P-256 point in uncompressed form consists of 0x04 (to denote that the point
// is uncompressed per SEC1 2.3.3) followed by two, 32-byte field elements.
const size_t kUncompressedPointBytes = 1 + 2 * 32;
// Precomputed private/public key-pair. Keys are stored on disk, so previously
// created values must continue to be usable for computing shared secrets.
const char kBobPrivateKey[] =
"MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgS8wRbDOWz0lKExvIVQiRKtPAP8"
"dgHUHAw5gyOd5d4jKhRANCAARZb49Va5MD/KcWtc0oiWc2e8njBDtQzj0mzcOl1fDSt16Pvu6p"
"fTU3MTWnImDNnkPxtXm58K7Uax8jFxA4TeXJ";
const char kBobPublicKey[] =
"BFlvj1VrkwP8pxa1zSiJZzZ7yeMEO1DOPSbNw6XV8NK3Xo++7ql9NTcxNaciYM2eQ/G1ebnwrt"
"RrHyMXEDhN5ck=";
const char kCarolPrivateKey[] =
"MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgmqy/ighwCm+RBP4Kct3rzaFEJ"
"CZhokknro3KYsriurChRANCAAScr5sTsqmlP8SqiI+8fzxVLr1pby2HyG5mC5J0WSpYVIpMNS"
"C16k1qcxqOJ4fiv8Ya47FYw/MIS7X1kobK27mP";
const char kCarolPublicKey[] =
"BJyvmxOyqaU/xKqIj7x/PFUuvWlvLYfIbmYLknRZKlhUikw1ILXqTWpzGo4nh+K/xhrjsVjD8"
"whLtfWShsrbuY8=";
// The shared secret between Bob and Carol.
const char kBobCarolSharedSecret[] =
"AUNmKkgLLVLf6j/VnA9Eg1CiPSPfQHGirQj79n4vOyw=";
TEST(P256KeyUtilTest, UniqueKeyPairGeneration) {
// Canary for determining that no key repetitions are found in few iterations.
std::set<std::string> seen_private_keys;
std::set<std::string> seen_public_keys;
for (int iteration = 0; iteration < 10; ++iteration) {
SCOPED_TRACE(iteration);
std::string private_key, public_key;
std::unique_ptr<crypto::ECPrivateKey> key(crypto::ECPrivateKey::Create());
ASSERT_TRUE(key);
ASSERT_TRUE(GetRawPublicKey(*key, &public_key));
ASSERT_TRUE(GetRawPrivateKey(*key, &private_key));
EXPECT_NE(private_key, public_key);
EXPECT_GT(private_key.size(), 0u);
EXPECT_EQ(public_key.size(), kUncompressedPointBytes);
EXPECT_EQ(0u, seen_private_keys.count(private_key));
EXPECT_EQ(0u, seen_public_keys.count(public_key));
seen_private_keys.insert(private_key);
seen_public_keys.insert(public_key);
}
}
TEST(P256KeyUtilTest, SharedSecretCalculation) {
std::unique_ptr<crypto::ECPrivateKey> bob_key =
crypto::ECPrivateKey::Create();
std::unique_ptr<crypto::ECPrivateKey> alice_key =
crypto::ECPrivateKey::Create();
std::string alice_public_key, bob_public_key, alice_private_key,
bob_private_key;
ASSERT_TRUE(GetRawPublicKey(*bob_key, &bob_public_key));
ASSERT_TRUE(GetRawPublicKey(*alice_key, &alice_public_key));
ASSERT_TRUE(GetRawPrivateKey(*bob_key, &bob_private_key));
ASSERT_TRUE(GetRawPrivateKey(*alice_key, &alice_private_key));
ASSERT_NE(bob_public_key, alice_public_key);
ASSERT_NE(bob_private_key, alice_private_key);
std::string bob_shared_secret, alice_shared_secret;
ASSERT_TRUE(
ComputeSharedP256Secret(*bob_key, alice_public_key, &bob_shared_secret));
ASSERT_TRUE(ComputeSharedP256Secret(*alice_key, bob_public_key,
&alice_shared_secret));
EXPECT_GT(bob_shared_secret.size(), 0u);
EXPECT_EQ(bob_shared_secret, alice_shared_secret);
std::string unused_shared_secret;
// Empty and too short peer public values should be considered invalid.
ASSERT_FALSE(ComputeSharedP256Secret(*bob_key, "", &unused_shared_secret));
ASSERT_FALSE(ComputeSharedP256Secret(*bob_key, bob_public_key.substr(1),
&unused_shared_secret));
}
TEST(P256KeyUtilTest, SharedSecretWithPreExistingKey) {
std::string bob_private_key, bob_public_key;
ASSERT_TRUE(base::Base64Decode(kBobPrivateKey, &bob_private_key));
ASSERT_TRUE(base::Base64Decode(kBobPublicKey, &bob_public_key));
std::vector<uint8_t> bob_private_key_vec(
bob_private_key.begin(), bob_private_key.end());
std::unique_ptr<crypto::ECPrivateKey> bob_key =
crypto::ECPrivateKey::CreateFromPrivateKeyInfo(bob_private_key_vec);
ASSERT_TRUE(bob_key);
// First verify against a newly created, ephemeral key-pair.
std::unique_ptr<crypto::ECPrivateKey> alice_key(
crypto::ECPrivateKey::Create());
std::string alice_public_key;
ASSERT_TRUE(GetRawPublicKey(*alice_key, &alice_public_key));
std::string bob_shared_secret, alice_shared_secret;
ASSERT_TRUE(ComputeSharedP256Secret(*bob_key, alice_public_key,
&bob_shared_secret));
ASSERT_TRUE(ComputeSharedP256Secret(*alice_key, bob_public_key,
&alice_shared_secret));
EXPECT_GT(bob_shared_secret.size(), 0u);
EXPECT_EQ(bob_shared_secret, alice_shared_secret);
std::string carol_private_key, carol_public_key;
ASSERT_TRUE(base::Base64Decode(kCarolPrivateKey, &carol_private_key));
ASSERT_TRUE(base::Base64Decode(kCarolPublicKey, &carol_public_key));
std::vector<uint8_t> carol_private_key_vec(
carol_private_key.begin(), carol_private_key.end());
std::unique_ptr<crypto::ECPrivateKey> carol_key =
crypto::ECPrivateKey::CreateFromPrivateKeyInfo(carol_private_key_vec);
ASSERT_TRUE(carol_key);
bob_shared_secret.clear();
std::string carol_shared_secret;
// Then verify against another stored key-pair and shared secret.
ASSERT_TRUE(ComputeSharedP256Secret(*bob_key, carol_public_key,
&bob_shared_secret));
ASSERT_TRUE(ComputeSharedP256Secret(*carol_key, bob_public_key,
&carol_shared_secret));
EXPECT_GT(carol_shared_secret.size(), 0u);
EXPECT_EQ(carol_shared_secret, bob_shared_secret);
std::string bob_carol_shared_secret;
ASSERT_TRUE(base::Base64Decode(
kBobCarolSharedSecret, &bob_carol_shared_secret));
EXPECT_EQ(carol_shared_secret, bob_carol_shared_secret);
}
} // namespace
} // namespace gcm
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