net/quic/crypto/null_decrypter.h

// Copyright (c) 2012 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_NULL_DECRYPTER_H_
#define NET_QUIC_CRYPTO_NULL_DECRYPTER_H_

#include "base/compiler_specific.h"
#include "net/base/net_export.h"
#include "net/quic/crypto/quic_decrypter.h"

namespace net {

class QuicDataReader;

// A NullDecrypter is a QuicDecrypter used before a crypto negotiation
// has occurred.  It does not actually decrypt the payload, but does
// verify a hash (fnv128) over both the payload and associated data.
class NET_EXPORT_PRIVATE NullDecrypter : public QuicDecrypter {
 public:
  explicit NullDecrypter(bool use_short_hash);
  virtual ~NullDecrypter() {}

  // QuicDecrypter implementation
  virtual bool SetKey(base::StringPiece key) OVERRIDE;
  virtual bool SetNoncePrefix(base::StringPiece nonce_prefix) OVERRIDE;
  virtual bool Decrypt(base::StringPiece nonce,
                       base::StringPiece associated_data,
                       base::StringPiece ciphertext,
                       unsigned char* output,
                       size_t* output_length) OVERRIDE;
  virtual QuicData* DecryptPacket(QuicPacketSequenceNumber sequence_number,
                                  base::StringPiece associated_data,
                                  base::StringPiece ciphertext) OVERRIDE;
  virtual base::StringPiece GetKey() const OVERRIDE;
  virtual base::StringPiece GetNoncePrefix() const OVERRIDE;

 private:
  bool ReadHash(QuicDataReader* reader, uint128* hash);
  uint128 ComputeHash(const std::string& data) const;
  bool use_short_hash_;
};

}  // namespace net

#endif  // NET_QUIC_CRYPTO_NULL_DECRYPTER_H_