net/quic/crypto/null_encrypter.cc

   1 // Copyright (c) 2012 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 #include "net/quic/crypto/null_encrypter.h"
   6 #include "net/quic/quic_data_writer.h"
   7 #include "net/quic/quic_utils.h"
   8
   9 using base::StringPiece;
  10 using std::string;
  11
  12 namespace net {
  13
  14 const size_t kHashSizeShort = 12;  // size of uint128 serialized short
  15
  16 NullEncrypter::NullEncrypter() {}
  17
  18 bool NullEncrypter::SetKey(StringPiece key) { return key.empty(); }
  19
  20 bool NullEncrypter::SetNoncePrefix(StringPiece nonce_prefix) {
  21   return nonce_prefix.empty();
  22 }
  23
  24 bool NullEncrypter::Encrypt(
  25     StringPiece /*nonce*/,
  26     StringPiece associated_data,
  27     StringPiece plaintext,
  28     unsigned char* output) {
  29   string buffer = associated_data.as_string();
  30   plaintext.AppendToString(&buffer);
  31   uint128 hash = QuicUtils::FNV1a_128_Hash(buffer.data(), buffer.length());
  32   QuicUtils::SerializeUint128Short(hash, output);
  33   memcpy(output + GetHashLength(), plaintext.data(), plaintext.size());
  34   return true;
  35 }
  36
  37 bool NullEncrypter::EncryptPacket(QuicPacketSequenceNumber /*sequence_number*/,
  38                                   StringPiece associated_data,
  39                                   StringPiece plaintext,
  40                                   char* output,
  41                                   size_t* output_length,
  42                                   size_t max_output_length) {
  43   const size_t len = plaintext.size() + GetHashLength();
  44   if (max_output_length < len) {
  45     return false;
  46   }
  47   Encrypt(StringPiece(), associated_data, plaintext,
  48           reinterpret_cast<unsigned char*>(output));
  49   *output_length = len;
  50   return true;
  51 }
  52
  53 size_t NullEncrypter::GetKeySize() const { return 0; }
  54
  55 size_t NullEncrypter::GetNoncePrefixSize() const { return 0; }
  56
  57 size_t NullEncrypter::GetMaxPlaintextSize(size_t ciphertext_size) const {
  58   return ciphertext_size - GetHashLength();
  59 }
  60
  61 size_t NullEncrypter::GetCiphertextSize(size_t plaintext_size) const {
  62   return plaintext_size + GetHashLength();
  63 }
  64
  65 StringPiece NullEncrypter::GetKey() const { return StringPiece(); }
  66
  67 StringPiece NullEncrypter::GetNoncePrefix() const { return StringPiece(); }
  68
  69 size_t NullEncrypter::GetHashLength() const {
  70   return kHashSizeShort;
  71 }
  72
  73 }  // namespace net