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
TransportEncryptionHandler()16 TransportEncryptionHandler::TransportEncryptionHandler()
17 : key_(), encryptor_(), iv_mask_(), initialized_(false) {}
18
~TransportEncryptionHandler()19 TransportEncryptionHandler::~TransportEncryptionHandler() {}
20
Initialize(std::string aes_key,std::string aes_iv_mask)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
Encrypt(uint32 frame_id,const base::StringPiece & data,std::string * encrypted_data)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
Decrypt(uint32 frame_id,const base::StringPiece & ciphertext,std::string * plaintext)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
77