diff --git a/keymaster/4.1/IOperation.hal b/keymaster/4.1/IOperation.hal
new file mode 100644
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+++ b/keymaster/4.1/IOperation.hal
@@ -0,0 +1,31 @@
+/*
+ * 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.keymaster@4.1;
+
+import @4.0::ErrorCode;
+import @4.0::OperationHandle;
+
+/**
+ * IOperation represents an in-progress IKeymasterDevice operation.  It is returned by
+ * IKeymasterDevice.beginOp().
+ */
+interface IOperation {
+    /**
+     * Returns the operation handle to be used as an authentication challenge.
+     */
+    getOperationChallenge() generates (ErrorCode error, OperationHandle operation);
+};