shaka-packager/media/base/key_source.h

117 lines
4.2 KiB
C++

// Copyright 2014 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#ifndef MEDIA_BASE_KEY_SOURCE_H_
#define MEDIA_BASE_KEY_SOURCE_H_
#include <vector>
#include "base/memory/scoped_ptr.h"
#include "media/base/status.h"
namespace media {
struct EncryptionKey {
EncryptionKey();
~EncryptionKey();
std::vector<uint8> key_id;
std::vector<uint8> key;
std::vector<uint8> pssh;
std::vector<uint8> iv;
};
/// KeySource is responsible for encryption key acquisition.
class KeySource {
public:
enum TrackType {
TRACK_TYPE_UNKNOWN = 0,
TRACK_TYPE_SD = 1,
TRACK_TYPE_HD = 2,
TRACK_TYPE_AUDIO = 3,
NUM_VALID_TRACK_TYPES = 3
};
virtual ~KeySource();
/// Fetch keys for CENC from the key server.
/// @param content_id the unique id identify the content.
/// @param policy specifies the DRM content rights.
/// @return OK on success, an error status otherwise.
virtual Status FetchKeys(const std::vector<uint8>& content_id,
const std::string& policy);
/// Fetch keys for CENC from the key server.
/// @param pssh_data is the Data portion of the PSSH box for the content
/// to be decrypted.
/// @return OK on success, an error status otherwise.
virtual Status FetchKeys(const std::vector<uint8>& pssh_data);
/// Get encryption key of the specified track type.
/// @param track_type is the type of track for which retrieving the key.
/// @param key is a pointer to the EncryptionKey which will hold the retrieved
/// key. Owner retains ownership, and may not be NULL.
/// @return OK on success, an error status otherwise.
virtual Status GetKey(TrackType track_type, EncryptionKey* key);
/// Get the encryption key specified by the CENC key ID.
/// @param key_id is the unique identifier for the key being retreived.
/// @param key is a pointer to the EncryptionKey which will hold the retrieved
/// key. Owner retains ownership, and may not be NULL.
/// @return OK on success, or an error status otherwise.
virtual Status GetKey(const std::vector<uint8>& key_id, EncryptionKey* key);
/// Get encryption key of the specified track type at the specified index.
/// @param crypto_period_index is the sequence number of the key rotation
/// period for which the key is being retrieved.
/// @param track_type is the type of track for which retrieving the key.
/// @param key is a pointer to the EncryptionKey which will hold the retrieved
/// key. Owner retains ownership, and may not be NULL.
/// @return OK on success, an error status otherwise.
virtual Status GetCryptoPeriodKey(uint32 crypto_period_index,
TrackType track_type,
EncryptionKey* key);
/// Create KeySource object from hex strings.
/// @param key_id_hex is the key id in hex string.
/// @param key_hex is the key in hex string.
/// @param pssh_data_hex is the pssh_data in hex string.
/// @param iv_hex is the IV in hex string. If not specified, a randomly
/// generated IV with the default length will be used.
/// Note: GetKey on the created key source will always return the same key
/// for all track types.
static scoped_ptr<KeySource> CreateFromHexStrings(
const std::string& key_id_hex,
const std::string& key_hex,
const std::string& pssh_data_hex,
const std::string& iv_hex);
/// Convert string representation of track type to enum representation.
static TrackType GetTrackTypeFromString(const std::string& track_type_string);
/// Convert TrackType to string.
static std::string TrackTypeToString(TrackType track_type);
protected:
KeySource();
/// @return the raw bytes of the pssh box with system ID and box header
/// included.
static std::vector<uint8> PsshBoxFromPsshData(
const std::vector<uint8>& pssh_data);
private:
explicit KeySource(scoped_ptr<EncryptionKey> encryption_key);
scoped_ptr<EncryptionKey> encryption_key_;
DISALLOW_COPY_AND_ASSIGN(KeySource);
};
} // namespace media
#endif // MEDIA_BASE_KEY_SOURCE_H_