diff --git a/cas/1.1/IMediaCasService.hal b/cas/1.1/IMediaCasService.hal
new file mode 100644
index 0000000..e82b54c
--- /dev/null
+++ b/cas/1.1/IMediaCasService.hal
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.hardware.cas@1.1;
+
+import @1.1::ICas;
+import @1.1::ICasListener;
+import @1.0::IMediaCasService;
+
+/**
+ * IMediaCasService is the main entry point for interacting with a vendor's
+ * cas HAL to create cas and descrambler plugin instances. A cas plugin instance
+ * opens cas sessions which are used to obtain keys for a descrambler session,
+ * which can in turn be used to descramble protected video content.
+ */
+
+interface IMediaCasService extends @1.0::IMediaCasService {
+    /**
+     * Construct a new instance of a @1.1 ICAS CasPlugin given a CA_system_id.
+     *
+     * @param caSystemId the id of the CA system.
+     * @param listener the event listener to receive events coming from the CasPlugin.
+     * @return cas the newly created CasPlugin interface.
+     */
+    createPluginExt(int32_t caSystemId, ICasListener listener) generates (ICas cas);
+};