Relanding Porting of HKDF changes from server.

crypto/hkdf_unittest.cc

+// 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.
+
+#include "crypto/hkdf.h"
+
+#include <string>
+
+#include "base/strings/string_number_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using crypto::HKDF;
+
+namespace test {
+namespace {
+
+struct HKDFTest {
+  const char* key_hex;
+  const char* salt_hex;
+  const char* info_hex;
+  const char* output_hex;
+};
+
+// These test cases are taken from
+// https://tools.ietf.org/html/rfc5869#appendix-A.
+static const HKDFTest kHKDFTests[] = {{
+    "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
+    "000102030405060708090a0b0c",
+    "f0f1f2f3f4f5f6f7f8f9",
+    "3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5"
+    "b887185865",
+  }, {
+    "000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f2021222324"
+    "25262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f40414243444546474849"
+    "4a4b4c4d4e4f",
+    "606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f8081828384"
+    "85868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9"
+    "aaabacadaeaf",
+    "b0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4"
+    "d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9"
+    "fafbfcfdfeff",
+    "b11e398dc80327a1c8e7f78c596a49344f012eda2d4efad8a050cc4c19afa97c59045a99ca"
+    "c7827271cb41c65e590e09da3275600c2f09b8367793a9aca3db71cc30c58179ec3e87c14c"
+    "01d5c1f3434f1d87",
+  }, {
+    "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
+    "",
+    "",
+    "8da4e775a563c18f715f802a063c5a31b8a11f5c5ee1879ec3454e5f3c738d2d9d201395fa"
+    "a4b61a96c8",
+  },
+};
+
+TEST(HKDFTest, HKDF) {
+  for (size_t i = 0; i < arraysize(kHKDFTests); i++) {
+    const HKDFTest& test(kHKDFTests[i]);
+    SCOPED_TRACE(i);
+
+    std::vector<uint8> data;
+    ASSERT_TRUE(base::HexStringToBytes(test.key_hex, &data));
+    const std::string key(reinterpret_cast<char *>(&data[0]), data.size());

[Ryan Sleevi, 2013/02/23 00:44:06]

style: reinterpret_cast<char *> -> reinterpret_cast<char*>

see also below

[ramant (doing other things), 2013/02/23 00:50:40]

Done.

+
+    data.clear();
+    // |salt_hex| could be optional.

[Ryan Sleevi, 2013/02/23 00:44:06]

// |salt_hex| is optional and may be empty.


That is, you would say "could be missing" or "is optional", but you generally
don't say something "could be optional" (because the opposite of "could be
optional" is "could be required", and those are mutually exclusive expressions),
unless it's only optional when some OTHER criteria is met (eg: "salt" could be
optional when data is less than 128 bytes, for example)

[ramant (doing other things), 2013/02/23 00:50:40]

Done.

+    std::string salt(test.salt_hex);
+    if (!salt.empty()) {
+      ASSERT_TRUE(base::HexStringToBytes(salt, &data));
+      salt.assign(reinterpret_cast<char *>(&data[0]), data.size());
+    }
+
+    data.clear();
+    // |info_hex| could be optional.
+    std::string info(test.info_hex);
+    if (!info.empty()) {
+      ASSERT_TRUE(base::HexStringToBytes(info, &data));
+      info.assign(reinterpret_cast<char *>(&data[0]), data.size());
+    }
+
+    data.clear();
+    ASSERT_TRUE(base::HexStringToBytes(test.output_hex, &data));
+    const std::string expected(reinterpret_cast<char *>(&data[0]), data.size());
+
+    // We set the key_length to the length of the expected output and then take
+    // the result from the first key, which is the client write key.
+    HKDF hkdf(key, salt, info, expected.size(), 0);
+
+    ASSERT_EQ(expected.size(), hkdf.client_write_key().size());
+    EXPECT_EQ(0, memcmp(expected.data(), hkdf.client_write_key().data(),
+                        expected.size()));
+  }
+}
+
+}  // namespace
+}  // namespace test