Add Aes128GcmEncrypter and Aes128GcmDecrypter

net/quic/crypto/aes_128_gcm_decrypter_nss.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/aes_128_gcm_decrypter.h"
+
+#include "base/memory/scoped_ptr.h"
+
+using base::StringPiece;
+
+namespace net {
+
+namespace {
+
+const size_t kKeySize = 16;
+const size_t kNoncePrefixSize = 4;
+const size_t kAuthTagSize = 16;
+
+}  // namespace
+
+// static
+bool Aes128GcmDecrypter::IsSupported() {
+  return false;
+}
+
+bool Aes128GcmDecrypter::SetKey(StringPiece key) {
+  if (key.size() != sizeof(key_)) {
+    return false;
+  }
+  memcpy(key_, key.data(), key.size());
+  return true;
+}
+
+bool Aes128GcmDecrypter::SetNoncePrefix(StringPiece nonce_prefix) {
+  if (nonce_prefix.size() != kNoncePrefixSize) {
+    return false;
+  }
+  memcpy(nonce_, nonce_prefix.data(), nonce_prefix.size());
+  return true;
+}
+
+QuicData* Aes128GcmDecrypter::Decrypt(QuicPacketSequenceNumber sequence_number,
+                                      StringPiece associated_data,
+                                      StringPiece ciphertext) {
+  COMPILE_ASSERT(sizeof(nonce_) == kNoncePrefixSize + sizeof(sequence_number),
+                 incorrect_nonce_size);
+  memcpy(nonce_ + kNoncePrefixSize, &sequence_number, sizeof(sequence_number));
+  return DecryptWithNonce(StringPiece(reinterpret_cast<char*>(nonce_),
+                                      sizeof(nonce_)),
+                          associated_data, ciphertext);
+}
+
+QuicData* Aes128GcmDecrypter::DecryptWithNonce(StringPiece nonce,
+                                               StringPiece associated_data,
+                                               StringPiece ciphertext) {
+  if (ciphertext.length() < kAuthTagSize) {
+    return NULL;
+  }
+  size_t plaintext_size = ciphertext.length() - kAuthTagSize;
+  scoped_ptr<char[]> plaintext(new char[plaintext_size]);
+
+  // TODO(wtc): implement this function using NSS.

[wtc, 2013/03/13 19:08:07]

Yes, we do. I added a stub implementation in this CL.
I will work on a real implementation later.

+
+  return new QuicData(plaintext.release(), plaintext_size, true);
+}
+
+}  // namespace net