media/cast/transport/utility/transport_encryption_handler.cc

   1 // Copyright 2014 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 "media/cast/transport/utility/transport_encryption_handler.h"
   6
   7 #include "base/logging.h"
   8 #include "crypto/encryptor.h"
   9 #include "crypto/symmetric_key.h"
  10 #include "media/cast/transport/cast_transport_defines.h"
  11
  12 namespace media {
  13 namespace cast {
  14 namespace transport {
  15
  16 TransportEncryptionHandler::TransportEncryptionHandler()
  17     : key_(), encryptor_(), iv_mask_(), initialized_(false) {}
  18
  19 TransportEncryptionHandler::~TransportEncryptionHandler() {}
  20
  21 bool TransportEncryptionHandler::Initialize(std::string aes_key,
  22                                             std::string aes_iv_mask) {
  23   initialized_ = false;
  24   if (aes_iv_mask.size() == kAesKeySize && aes_key.size() == kAesKeySize) {
  25     iv_mask_ = aes_iv_mask;
  26     key_.reset(
  27         crypto::SymmetricKey::Import(crypto::SymmetricKey::AES, aes_key));
  28     encryptor_.reset(new crypto::Encryptor());
  29     encryptor_->Init(key_.get(), crypto::Encryptor::CTR, std::string());
  30     initialized_ = true;
  31   } else if (aes_iv_mask.size() != 0 || aes_key.size() != 0) {
  32     DCHECK_EQ(aes_iv_mask.size(), 0u)
  33         << "Invalid Crypto configuration: aes_iv_mask.size";
  34     DCHECK_EQ(aes_key.size(), 0u)
  35         << "Invalid Crypto configuration: aes_key.size";
  36     return false;
  37   }
  38   return true;
  39 }
  40
  41 bool TransportEncryptionHandler::Encrypt(uint32 frame_id,
  42                                          const base::StringPiece& data,
  43                                          std::string* encrypted_data) {
  44   if (!initialized_)
  45     return false;
  46   if (!encryptor_->SetCounter(GetAesNonce(frame_id, iv_mask_))) {
  47     NOTREACHED() << "Failed to set counter";
  48     return false;
  49   }
  50   if (!encryptor_->Encrypt(data, encrypted_data)) {
  51     NOTREACHED() << "Encrypt error";
  52     return false;
  53   }
  54   return true;
  55 }
  56
  57 bool TransportEncryptionHandler::Decrypt(uint32 frame_id,
  58                                          const base::StringPiece& ciphertext,
  59                                          std::string* plaintext) {
  60   if (!initialized_) {
  61     return false;
  62   }
  63   if (!encryptor_->SetCounter(transport::GetAesNonce(frame_id, iv_mask_))) {
  64     NOTREACHED() << "Failed to set counter";
  65     return false;
  66   }
  67   if (!encryptor_->Decrypt(ciphertext, plaintext)) {
  68     VLOG(1) << "Decryption error";
  69     return false;
  70   }
  71   return true;
  72 }
  73
  74 }  // namespace transport
  75 }  // namespace cast
  76 }  // namespace media