Add ChaCha20Poly1305Encrypter, based on

net/quic/crypto/chacha20_poly1305_decrypter_test.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 "net/quic/crypto/chacha20_poly1305_decrypter.h"
+
+#include "net/quic/test_tools/quic_test_utils.h"
+
+using base::StringPiece;
+
+namespace {
+
+// The test vectors come from draft-agl-tls-chacha20poly1305-04 Section 7.
+
+// Each test vector consists of six strings of lowercase hexadecimal digits.
+// The strings may be empty (zero length). A test vector with a NULL |key|
+// marks the end of an array of test vectors.
+struct TestVector {
+  // Input:
+  const char* key;
+  const char* iv;
+  const char* aad;
+  const char* ct;
+
+  // Expected output:
+  const char* pt;  // An empty string "" means decryption succeeded and
+                   // the plaintext is zero-length. NULL means decryption
+                   // failed.
+};
+
+const TestVector test_vectors[] = {
+  { "4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
+        "0a1007",
+    "cd7cf67be39c794a",
+    "87e229d4500845a079c0",
+    "e3e446f7ede9a19b62a4677dabf4e3d24b876bb284753896e1d6",
+    "86d09974840bded2a5ca"
+  },
+  // Modify the ciphertext (ChaCha20 encryption output).
+  { "4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
+        "0a1007",
+    "cd7cf67be39c794a",
+    "87e229d4500845a079c0",
+    "f3e446f7ede9a19b62a4677dabf4e3d24b876bb284753896e1d6",
+    NULL  // FAIL
+  },
+  // Modify the ciphertext (Poly1305 authenticator).
+  { "4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
+        "0a1007",
+    "cd7cf67be39c794a",
+    "87e229d4500845a079c0",
+    "e3e446f7ede9a19b62a4677dabf4e3d24b876bb284753896e1d7",
+    NULL  // FAIL
+  },
+  // Modify the associated data.
+  { "4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
+        "0a1007",
+    "dd7cf67be39c794a",
+    "87e229d4500845a079c0",
+    "e3e446f7ede9a19b62a4677dabf4e3d24b876bb284753896e1d6",
+    NULL  // FAIL
+  },
+  { NULL }
+};
+
+}  // namespace
+
+namespace net {
+namespace test {
+
+// DecryptWithNonce wraps the |Decrypt| method of |decrypter| to allow passing
+// in an nonce and also to allocate the buffer needed for the plaintext.
+QuicData* DecryptWithNonce(ChaCha20Poly1305Decrypter* decrypter,
+                           StringPiece nonce,
+                           StringPiece associated_data,
+                           StringPiece ciphertext) {
+  size_t plaintext_size = ciphertext.length();
+  scoped_ptr<char[]> plaintext(new char[plaintext_size]);
+
+  if (!decrypter->Decrypt(nonce, associated_data, ciphertext,
+                          reinterpret_cast<unsigned char*>(plaintext.get()),
+                          &plaintext_size)) {
+    return NULL;
+  }
+  return new QuicData(plaintext.release(), plaintext_size, true);
+}
+
+TEST(ChaCha20Poly1305DecrypterTest, Decrypt) {
+  if (!ChaCha20Poly1305Decrypter::IsSupported()) {
+    LOG(INFO) << "ChaCha20+Poly1305 not supported. Test skipped.";
+    return;
+  }
+
+  for (size_t i = 0; test_vectors[i].key != NULL; i++) {
+    // Decode the test vector.
+    string key;
+    string iv;
+    string aad;
+    string ct;
+    string pt;
+    ASSERT_TRUE(DecodeHexString(test_vectors[i].key, &key));
+    ASSERT_TRUE(DecodeHexString(test_vectors[i].iv, &iv));
+    ASSERT_TRUE(DecodeHexString(test_vectors[i].aad, &aad));
+    ASSERT_TRUE(DecodeHexString(test_vectors[i].ct, &ct));
+    if (test_vectors[i].pt) {
+      ASSERT_TRUE(DecodeHexString(test_vectors[i].pt, &pt));
+    }
+
+    ChaCha20Poly1305Decrypter decrypter;
+    ASSERT_TRUE(decrypter.SetKey(key));
+    scoped_ptr<QuicData> decrypted(DecryptWithNonce(
+        &decrypter, iv,
+        // This deliberately tests that the decrypter can handle an AAD that
+        // is set to NULL, as opposed to a zero-length, non-NULL pointer.
+        StringPiece(aad.length() ? aad.data() : NULL, aad.length()), ct));
+    if (!decrypted.get()) {
+      EXPECT_FALSE(test_vectors[i].pt);
+      continue;
+    }
+    EXPECT_TRUE(test_vectors[i].pt);
+
+    ASSERT_EQ(pt.length(), decrypted->length());
+    test::CompareCharArraysWithHexError("plaintext", decrypted->data(),
+                                        pt.length(), pt.data(), pt.length());
+  }
+}
+
+}  // namespace test
+}  // namespace net