82 lines
2.9 KiB
C++
82 lines
2.9 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef MEDIA_BASE_DECRYPT_CONFIG_H_
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#define MEDIA_BASE_DECRYPT_CONFIG_H_
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#include <stdint.h>
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#include <string>
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#include <vector>
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#include "packager/base/memory/scoped_ptr.h"
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#include "packager/media/base/encryption_modes.h"
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namespace edash_packager {
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namespace media {
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/// The Common Encryption spec provides for subsample encryption, where portions
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/// of a sample are not encrypted. A SubsampleEntry specifies the number of
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/// clear and encrypted bytes in each subsample. For decryption, all of the
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/// encrypted bytes in a sample should be considered a single logical stream,
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/// regardless of how they are divided into subsamples, and the clear bytes
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/// should not be considered as part of decryption. This is logically equivalent
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/// to concatenating all @a cipher_bytes portions of subsamples, decrypting that
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/// result, and then copying each byte from the decrypted block over the
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/// corresponding encrypted byte.
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struct SubsampleEntry {
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SubsampleEntry()
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: clear_bytes(0), cipher_bytes(0) {}
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SubsampleEntry(uint16_t clear_bytes, uint32_t cipher_bytes)
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: clear_bytes(clear_bytes), cipher_bytes(cipher_bytes) {}
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uint16_t clear_bytes;
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uint32_t cipher_bytes;
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};
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/// Contains all the information that a decryptor needs to decrypt a media
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/// sample.
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class DecryptConfig {
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public:
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/// Keys are always 128 bits.
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static const size_t kDecryptionKeySize = 16;
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/// @param key_id is the ID that references the decryption key.
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/// @param iv is the initialization vector defined by the encryptor.
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/// @param subsamples defines the clear and encrypted portions of the sample
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/// as described in SubsampleEntry. A decrypted buffer will be equal
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/// in size to the sum of the subsample sizes.
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/// @param decryption_mode decryption_mode is to determine which decryptor to
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/// use.
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DecryptConfig(const std::vector<uint8_t>& key_id,
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const std::vector<uint8_t>& iv,
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const std::vector<SubsampleEntry>& subsamples,
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EncryptionMode decryption_mode);
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~DecryptConfig();
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const std::vector<uint8_t>& key_id() const { return key_id_; }
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const std::vector<uint8_t>& iv() const { return iv_; }
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const std::vector<SubsampleEntry>& subsamples() const { return subsamples_; }
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EncryptionMode decryption_mode() const { return decryption_mode_; }
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private:
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const std::vector<uint8_t> key_id_;
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// Initialization vector.
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const std::vector<uint8_t> iv_;
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// Subsample information. May be empty for some formats, meaning entire frame
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// (less data ignored by data_offset_) is encrypted.
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const std::vector<SubsampleEntry> subsamples_;
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EncryptionMode decryption_mode_;
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DISALLOW_COPY_AND_ASSIGN(DecryptConfig);
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};
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} // namespace media
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} // namespace edash_packager
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#endif // MEDIA_BASE_DECRYPT_CONFIG_H_
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