// Copyright 2018 Google LLC. 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
//
// This file defines Widevine Common Encryption Request and Response proto
// format.

syntax = "proto2";

package shaka;

enum ModularDrmType { WIDEVINE = 0; }

message CommonEncryptionRequest {
  enum ProtectionScheme {
    UNSPECIFIED = 0;    // Defaults to 'cenc'
    CENC = 1667591779;  // 'cenc' (AES-CTR) = 0x63656E63
    CBC1 = 1667392305;  // 'cbc1' (AES-CBC) = 0x63626331
    CENS = 1667591795;  // 'cens' (AES-CTR subsample) =
                        // 0x63656E73
    CBCS = 1667392371;  //'cbcs' (AES-CBC subsample) = 0x63626373
  };
  // An identifier supplied by a content provider, used to identify
  // a piece of content and derive key IDs and content keys.
  optional bytes content_id = 1;

  // A policy name that refers to a stored policy in Widevine service.
  optional string policy = 2;

  // A list of tracks whose PSSHes and keys should be returned.
  message Track { optional string type = 1; }
  repeated Track tracks = 3;

  // Indicates the drm system types whose PSSH should be generated. An empty
  // list implies [ WIDEVINE ].
  repeated ModularDrmType drm_types = 4;

  // Optional starting period, if multiple keys are being requested for content
  // that will rotate keys.
  optional uint32 first_crypto_period_index = 8;

  // Optional count of periods to return keys for, starting with
  // first_crypto_period_index. If this count is set, then
  // first_crypto_period_index must be provided in the request as well.
  optional uint32 crypto_period_count = 9 [default = 1];

  // 'pssh' box data which can be used in lieu of the content_id field in order
  // to request keys for Widevine CENC content.
  optional bytes pssh_data = 10;

  // Widevine asset ID which can be used in lieu of the content_id field in
  // order to request keys for Widevine "Classic" packaged content.
  optional uint32 asset_id = 11;

  // Optional value which can be used to indicate a group.
  // If present the CommonEncryptionResponse will contain pssh data belonging
  // to this group.
  optional bytes group_id = 12;

  // Optional value representing the duration of each crypto period in seconds.
  optional uint32 crypto_period_seconds = 13;

  // Protection scheme identifying the encryption algorithm. The protection
  // scheme is represented as a uint32 value. The uint32 contains 4 bytes each
  // representing a single ascii character in one of the 4CC protection scheme
  // values.
  // The protection scheme to set in the generated 'pssh' box data.
  // This protection scheme value may be encoded into the content. If the
  // protection scheme is available in the content, it will supercede this
  // value.
  optional ProtectionScheme protection_scheme = 14;

  // Enable entitlement license if set to true.
  optional bool enable_entitlement_license = 16;

  // Video feature identifier, which is used in conjunction with |content_id|
  // to derive key IDs and content keys. For example, it can be used to generate
  // different keys for HDR and SDR. The value is propagated to PSSH.
  // Ignored for tracks with type “AUDIO”.
  // Current values are "HDR".
  optional string video_feature = 19;
}

message CommonEncryptionResponse {
  // Indicates the result of the operation.
  enum Status {
    OK = 0;
    SIGNATURE_FAILED = 1;
    CONTENT_ID_MISSING = 2;
    POLICY_UNKNOWN = 3;
    TRACK_TYPE_MISSING = 4;
    TRACK_TYPE_UNKNOWN = 5;
    MALFORMED_REQUEST = 6;
    ACCESS_DENIED = 7;
    INTERNAL_ERROR = 8;
    INVALID_WIDEVINE_PSSH = 9;
    TOO_MANY_CONTENT_SPECIFIERS = 10;
    ASSET_NOT_FOUND = 11;
    ASSET_MISSING_KEY = 12;
    CONTENT_ID_MISMATCH = 13;
    KEY_ID_MISMATCH = 14;
    INVALID_GROUP_TRACK_TYPE = 15;
    KEY_ROTATION_WITH_UNSUPPORTED_DRM_TYPE = 16;
    NO_REQUESTED_CRYPTO_PERIODS = 17;
  };
  optional Status status = 1;

  // A list of DRM systems whose PSSH is returned.
  message Drm {
    // The DRM system, e.g. widevine or playready.
    optional ModularDrmType type = 1;

    // Registered system Id for the DRM system.
    optional string system_id = 2;
  }
  repeated Drm drm = 3;

  // A list of tracks and their PSSH and key data. If crypto_period_count
  // was given in the request, then there will be a separate Track message
  // in the response for each period.
  message Track {
    // Track type. SD, HD, UHD1, UHD2 or AUDIO.
    optional string type = 1;
    optional bytes key_id = 2;
    optional bytes key = 3;
    optional bytes iv = 4;

    message Pssh {
      optional ModularDrmType drm_type = 1;
      // Contains only PSSH data, i.e. no PSSH box header.
      // Can be omitted if |boxes| is present.
      // This field should become deprecated as it may not be populated when
      // entitlement licenses become more widely used.
      optional bytes data = 2;
      // Contains full PSSH boxes (there can be more than one PSSH box).
      // Always populated.
      optional bytes boxes = 3;
    }
    repeated Pssh pssh = 5;
    optional uint32 crypto_period_index = 6;
  }
  repeated Track tracks = 4;

  // The content_id associated with the response.  The content_id is either
  // the content_id from the request or from the PSSH in the request.
  optional bytes content_id = 6;
}

// A generic protobuf used as the request format of various Modular DRM APIs.
message SignedModularDrmRequest {
  optional bytes request = 1;
  optional bytes signature = 2;
  // Identifies the entity sending / signing the request.
  optional string signer = 3;
}

message SignedModularDrmResponse {
  optional bytes response = 1;
  optional bytes signature = 2;
}