85 lines
2.7 KiB
C++
85 lines
2.7 KiB
C++
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// Copyright 2018 Google LLC. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#include "packager/media/crypto/aes_encryptor_factory.h"
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#include "packager/media/base/aes_encryptor.h"
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#include "packager/media/base/aes_pattern_cryptor.h"
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#include "packager/media/crypto/sample_aes_ec3_cryptor.h"
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namespace shaka {
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namespace media {
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std::unique_ptr<AesCryptor> AesEncryptorFactory::CreateEncryptor(
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FourCC protection_scheme,
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uint8_t crypt_byte_block,
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uint8_t skip_byte_block,
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Codec codec,
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const std::vector<uint8_t>& key,
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const std::vector<uint8_t>& iv) {
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std::unique_ptr<AesCryptor> encryptor;
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switch (protection_scheme) {
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case FOURCC_cenc:
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encryptor.reset(new AesCtrEncryptor);
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break;
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case FOURCC_cbc1:
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encryptor.reset(new AesCbcEncryptor(kNoPadding));
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break;
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case FOURCC_cens:
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encryptor.reset(new AesPatternCryptor(
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crypt_byte_block, skip_byte_block,
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AesPatternCryptor::kEncryptIfCryptByteBlockRemaining,
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AesCryptor::kDontUseConstantIv,
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std::unique_ptr<AesCryptor>(new AesCtrEncryptor)));
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break;
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case FOURCC_cbcs:
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encryptor.reset(new AesPatternCryptor(
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crypt_byte_block, skip_byte_block,
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AesPatternCryptor::kEncryptIfCryptByteBlockRemaining,
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AesCryptor::kUseConstantIv,
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std::unique_ptr<AesCryptor>(new AesCbcEncryptor(kNoPadding))));
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break;
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case kAppleSampleAesProtectionScheme:
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if (crypt_byte_block == 0 && skip_byte_block == 0) {
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if (codec == kCodecEAC3) {
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encryptor.reset(new SampleAesEc3Cryptor(
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std::unique_ptr<AesCryptor>(new AesCbcEncryptor(kNoPadding))));
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} else {
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encryptor.reset(
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new AesCbcEncryptor(kNoPadding, AesCryptor::kUseConstantIv));
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}
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} else {
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encryptor.reset(new AesPatternCryptor(
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crypt_byte_block, skip_byte_block,
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AesPatternCryptor::kSkipIfCryptByteBlockRemaining,
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AesCryptor::kUseConstantIv,
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std::unique_ptr<AesCryptor>(new AesCbcEncryptor(kNoPadding))));
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}
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break;
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default:
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LOG(ERROR) << "Unsupported protection scheme.";
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return nullptr;
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}
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if (iv.empty()) {
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std::vector<uint8_t> random_iv;
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if (!AesCryptor::GenerateRandomIv(protection_scheme, &random_iv)) {
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LOG(ERROR) << "Failed to generate random iv.";
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return nullptr;
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}
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if (!encryptor->InitializeWithIv(key, random_iv))
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return nullptr;
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} else {
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if (!encryptor->InitializeWithIv(key, iv))
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return nullptr;
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}
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return encryptor;
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}
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} // namespace media
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} // namespace shaka
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