net/quic/crypto/crypto_secret_boxer.h

   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
  13 namespace net {
  14
  15 class 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.
  20 class 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_