1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef NET_QUIC_CRYPTO_CRYPTO_SECRET_BOXER_H_
6#define NET_QUIC_CRYPTO_CRYPTO_SECRET_BOXER_H_
7
8#include <string>
9
10#include "base/strings/string_piece.h"
11#include "net/base/net_export.h"
12
13namespace net {
14
15class QuicRandom;
16
17// CryptoSecretBoxer encrypts small chunks of plaintext (called 'boxing') and
18// then, later, can authenticate+decrypt the resulting boxes. This object is
19// thread-safe.
20class NET_EXPORT_PRIVATE CryptoSecretBoxer {
21 public:
22  CryptoSecretBoxer() {}
23
24  // GetKeySize returns the number of bytes in a key.
25  static size_t GetKeySize();
26
27  // SetKey sets the key for this object. This must be done before |Box| or
28  // |Unbox| are called. |key| must be |GetKeySize()| bytes long.
29  void SetKey(base::StringPiece key);
30
31  // Box encrypts |plaintext| using a random nonce generated from |rand| and
32  // returns the resulting ciphertext. Since an authenticator and nonce are
33  // included, the result will be slightly larger than |plaintext|.
34  std::string Box(QuicRandom* rand, base::StringPiece plaintext) const;
35
36  // Unbox takes the result of a previous call to |Box| in |ciphertext| and
37  // authenticates+decrypts it. If |ciphertext| is not authentic then it
38  // returns false. Otherwise, |out_storage| is used to store the result and
39  // |out| is set to point into |out_storage| and contains the original
40  // plaintext.
41  bool Unbox(base::StringPiece ciphertext,
42             std::string* out_storage,
43             base::StringPiece* out) const;
44
45 private:
46  std::string key_;
47
48  DISALLOW_COPY_AND_ASSIGN(CryptoSecretBoxer);
49};
50
51}  // namespace net
52
53#endif  // NET_QUIC_CRYPTO_CRYPTO_SECRET_BOXER_H_
54