Add Aes128GcmEncrypter and Aes128GcmDecrypter

net/quic/crypto/aes_128_gcm_encrypter_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_encrypter.h"
+
+#include <string.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 Aes128GcmEncrypter::IsSupported() {
+  return false;
+}
+
+bool Aes128GcmEncrypter::SetKey(StringPiece key) {
+  DCHECK_EQ(key.size(), sizeof(key_));
+  if (key.size() != sizeof(key_)) {
+    return false;
+  }
+  memcpy(key_, key.data(), key.size());
+  return true;
+}
+
+bool Aes128GcmEncrypter::SetNoncePrefix(StringPiece nonce_prefix) {
+  DCHECK_EQ(nonce_prefix.size(), kNoncePrefixSize);
+  if (nonce_prefix.size() != kNoncePrefixSize) {
+    return false;
+  }
+  memcpy(nonce_, nonce_prefix.data(), nonce_prefix.size());
+  return true;
+}
+
+QuicData* Aes128GcmEncrypter::Encrypt(QuicPacketSequenceNumber sequence_number,
+                                      StringPiece associated_data,
+                                      StringPiece plaintext) {
+  COMPILE_ASSERT(sizeof(nonce_) == kNoncePrefixSize + sizeof(sequence_number),
+                 incorrect_nonce_size);
+  memcpy(nonce_ + kNoncePrefixSize, &sequence_number, sizeof(sequence_number));
+  return EncryptWithNonce(StringPiece(reinterpret_cast<char*>(nonce_),
+                                      sizeof(nonce_)),
+                          associated_data, plaintext);
+}
+
+size_t Aes128GcmEncrypter::GetKeySize() const {
+  return kKeySize;
+}
+
+size_t Aes128GcmEncrypter::GetNoncePrefixSize() const {
+  return kNoncePrefixSize;
+}
+
+size_t Aes128GcmEncrypter::GetMaxPlaintextSize(size_t ciphertext_size) const {
+  return ciphertext_size - kAuthTagSize;
+}
+
+// An AEAD_AES_128_GCM ciphertext is exactly 16 bytes longer than its
+// corresponding plaintext.
+size_t Aes128GcmEncrypter::GetCiphertextSize(size_t plaintext_size) const {
+  return plaintext_size + kAuthTagSize;
+}
+
+QuicData* Aes128GcmEncrypter::EncryptWithNonce(StringPiece nonce,
+                                               StringPiece associated_data,
+                                               StringPiece plaintext) {
+  size_t ciphertext_size = GetCiphertextSize(plaintext.length());
+  scoped_ptr<char[]> ciphertext(new char[ciphertext_size]);
+
+  // TODO(wtc): implement this function using NSS.
+
+  return new QuicData(ciphertext.release(), ciphertext_size, true);
+}
+
+StringPiece Aes128GcmEncrypter::GetKey() const {
+  return StringPiece(reinterpret_cast<const char*>(key_), sizeof(key_));
+}
+
+StringPiece Aes128GcmEncrypter::GetNoncePrefix() const {
+  return StringPiece(reinterpret_cast<const char*>(nonce_), kNoncePrefixSize);
+}
+
+}  // namespace net