Support for group license

Content keys in ECM v3 can now additionally be encrypted by group
entitlement keys.

protos/public/media_cas.proto

@@ -22,6 +22,9 @@ message CaDescriptorPrivateData {
   // Entitlement key IDs for current content per track. Each track will allow up
   // to 2 entitlement key ids (odd and even entitlement keys).
   repeated bytes entitlement_key_ids = 3;
+
+  // The groups ids this channel belongs to.
+  repeated bytes group_ids = 4;
 }
 
 // Widevine fingerprinting.
@@ -49,6 +52,15 @@ message ServiceBlocking {
 message EmmPayload {
   repeated Fingerprinting fingerprinting = 1;
   repeated ServiceBlocking service_blocking = 2;
+  // Epoch time in seconds. The time when the EMM is generated.
+  optional int64 timestamp_secs = 3;
+}
+
+message SignedEmmPayload {
+  // Serialized EmmPayload.
+  optional bytes serialized_payload = 1;
+  // ECC (Elliptic Curve Cryptography) signature of |serialized_payload|.
+  optional bytes signature = 2;
 }
 
 message EcmMetaData {
@@ -89,6 +101,18 @@ message EcmKeyData {
   optional bytes content_iv = 4;
 }
 
+message EcmGroupKeyData {
+  // Group id of this key data.
+  optional bytes group_id = 1;
+  // Required. The key data for the even slot. Fields wrapped_key_iv and
+  // content_iv may be omitted if it is the same as EcmPayload.even_key_data.
+  optional EcmKeyData even_key_data = 2;
+  // Optional. The key data for the odd slot if key rotation is enabled. Fields
+  // wrapped_key_iv and content_iv may be omitted if it is the same as
+  // EcmPayload.odd_key_data.
+  optional EcmKeyData odd_key_data = 3;
+}
+
 message EcmPayload {
   // Required. Meta info carried by the ECM.
   optional EcmMetaData meta_data = 1;
@@ -100,6 +124,9 @@ message EcmPayload {
   optional Fingerprinting fingerprinting = 4;
   // Optional. Widevine service blocking information.
   optional ServiceBlocking service_blocking = 5;
+  // If a channel belongs to a group, the content keys can additionally be
+  // encrypted by the group entitlement keys.
+  repeated EcmGroupKeyData group_key_data = 6;
 }
 
 // The payload field for an ECM with signature.