Add Aes128GcmEncrypter and Aes128GcmDecrypter

net/quic/crypto/aes_128_gcm_encrypter.h

+// 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.
+
+#ifndef NET_QUIC_CRYPTO_AES_128_GCM_ENCRYPTER_H_
+#define NET_QUIC_CRYPTO_AES_128_GCM_ENCRYPTER_H_
+
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "net/quic/crypto/quic_encrypter.h"
+
+namespace net {
+
+namespace test {
+class Aes128GcmEncrypterPeer;
+}  // namespace test
+
+// An Aes128GcmEncrypter is a QuicEncrypter that implements the
+// AEAD_AES_128_GCM algorithm specified in RFC 5116. Create an instance by
+// calling QuicEncrypter::Create(kAESG).
+//
+// It uses an authentication tag of 16 bytes (128 bits). The fixed prefix
+// of the nonce is four bytes.
+class NET_EXPORT_PRIVATE Aes128GcmEncrypter : public QuicEncrypter {
+ public:
+  virtual ~Aes128GcmEncrypter() {}
+
+  // Returns true if the underlying crypto library supports AES GCM.
+#if defined(USE_OPENSSL)
+  static bool IsSupported() { return true; }
+#else
+  static bool IsSupported();
+#endif
+
+  // QuicEncrypter implementation
+  virtual bool SetKey(base::StringPiece key) OVERRIDE;
+  virtual bool SetNoncePrefix(base::StringPiece nonce_prefix) OVERRIDE;
+  virtual QuicData* Encrypt(QuicPacketSequenceNumber sequence_number,
+                            base::StringPiece associated_data,
+                            base::StringPiece plaintext) OVERRIDE;
+  virtual size_t GetKeySize() const OVERRIDE;
+  virtual size_t GetNoncePrefixSize() const OVERRIDE;
+  virtual size_t GetMaxPlaintextSize(size_t ciphertext_size) const OVERRIDE;
+  virtual size_t GetCiphertextSize(size_t plaintext_size) const OVERRIDE;
+  virtual base::StringPiece GetKey() const OVERRIDE;
+  virtual base::StringPiece GetNoncePrefix() const OVERRIDE;
+
+ private:
+  friend class test::Aes128GcmEncrypterPeer;
+
+  // The same as Encrypt(), except that the supplied |nonce| argument rather
+  // than the |nonce_| member is used as the nonce. This method is useful
+  // for testing the underlying AES GCM implementation.
+  QuicData* EncryptWithNonce(base::StringPiece nonce,
+                             base::StringPiece associated_data,
+                             base::StringPiece plaintext);
+
+  // The 128-bit AES key.
+  unsigned char key_[16];
+  // The nonce, a concatenation of a four-byte fixed prefix and a 8-byte
+  // packet sequence number.
+  unsigned char nonce_[12];
+};
+
+}  // namespace net
+
+#endif  // NET_QUIC_CRYPTO_AES_128_GCM_ENCRYPTER_H_