diff --git a/keymaster/aidl/Android.bp b/keymaster/aidl/Android.bp
new file mode 100644
index 0000000..a2d73ead
--- /dev/null
+++ b/keymaster/aidl/Android.bp
@@ -0,0 +1,18 @@
+aidl_interface {
+    name: "android.hardware.keymaster",
+    vendor_available: true,
+    srcs: [
+        "android/hardware/keymaster/*.aidl",
+    ],
+    stability: "vintf",
+    backend: {
+        java: {
+            platform_apis: true,
+        },
+        ndk: {
+            vndk: {
+                enabled: true,
+            },
+        },
+    },
+}
diff --git a/keymaster/aidl/android/hardware/keymaster/HardwareAuthToken.aidl b/keymaster/aidl/android/hardware/keymaster/HardwareAuthToken.aidl
new file mode 100644
index 0000000..58602aa
--- /dev/null
+++ b/keymaster/aidl/android/hardware/keymaster/HardwareAuthToken.aidl
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2020 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;
+
+import android.hardware.keymaster.Timestamp;
+import android.hardware.keymaster.HardwareAuthenticatorType;
+
+/**
+ * HardwareAuthToken is used to prove successful user authentication, to unlock the use of a key.
+ *
+ * HardwareAuthTokens are produced by other secure environment applications, notably GateKeeper and
+ * Fingerprint, in response to successful user authentication events.  These tokens are passed to
+ * begin(), update(), and finish() to prove that authentication occurred.  See those methods for
+ * more details.  It is up to the caller to determine which of the generated auth tokens is
+ * appropriate for a given key operation.
+ */
+@VintfStability
+parcelable HardwareAuthToken {
+
+    /**
+     * challenge is a value that's used to enable authentication tokens to authorize specific
+     * events.  The primary use case for challenge is to authorize an IKeymasterDevice cryptographic
+     * operation, for keys that require authentication per operation. See begin() for details.
+     */
+    long challenge;
+
+    /**
+     *  userId is the a "secure" user ID.  It is not related to any Android user ID or UID, but is
+     *  created in the Gatekeeper application in the secure environment.
+     */
+    long userId;
+
+    /**
+     *  authenticatorId is the a "secure" user ID.  It is not related to any Android user ID or UID,
+     *  but is created in an authentication application in the secure environment, such as the
+     *  Fingerprint application.
+     */
+    long authenticatorId;  // Secure authenticator ID.
+
+    /**
+     * authenticatorType describes the type of authentication that took place, e.g. password or
+     * fingerprint.
+     */
+    HardwareAuthenticatorType authenticatorType;
+
+    /**
+     * timestamp indicates when the user authentication took place, in milliseconds since some
+     * starting point (generally the most recent device boot) which all of the applications within
+     * one secure environment must agree upon.  This timestamp is used to determine whether or not
+     * the authentication occurred recently enough to unlock a key (see Tag::AUTH_TIMEOUT).
+     */
+    Timestamp timestamp;
+
+    /**
+     * MACs are computed with a backward-compatible method, used by Keymaster 3.0, Gatekeeper 1.0
+     * and Fingerprint 1.0, as well as pre-treble HALs.
+     *
+     * The MAC is Constants::AUTH_TOKEN_MAC_LENGTH bytes in length and is computed as follows:
+     *
+     *     HMAC_SHA256(
+     *         H, 0 || challenge || user_id || authenticator_id || authenticator_type || timestamp)
+     *
+     * where ``||'' represents concatenation, the leading zero is a single byte, and all integers
+     * are represented as unsigned values, the full width of the type.  The challenge, userId and
+     * authenticatorId values are in machine order, but authenticatorType and timestamp are in
+     * network order (big-endian).  This odd construction is compatible with the hw_auth_token_t
+     * structure,
+     *
+     * Note that mac is a vec rather than an array, not because it's actually variable-length but
+     * because it could be empty.  As documented in the IKeymasterDevice::begin,
+     * IKeymasterDevice::update and IKeymasterDevice::finish doc comments, an empty mac indicates
+     * that this auth token is empty.
+     */
+    byte[] mac;
+}
diff --git a/keymaster/aidl/android/hardware/keymaster/HardwareAuthenticatorType.aidl b/keymaster/aidl/android/hardware/keymaster/HardwareAuthenticatorType.aidl
new file mode 100644
index 0000000..3141858
--- /dev/null
+++ b/keymaster/aidl/android/hardware/keymaster/HardwareAuthenticatorType.aidl
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2020 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;
+
+/**
+ * Hardware authentication type, used by HardwareAuthTokens to specify the mechanism used to
+ * authentiate the user, and in KeyCharacteristics to specify the allowable mechanisms for
+ * authenticating to activate a key.
+ */
+@VintfStability
+@Backing(type="int")
+enum HardwareAuthenticatorType {
+    NONE = 0,
+    PASSWORD = 1 << 0,
+    FINGERPRINT = 1 << 1,
+    // Additional entries must be powers of 2.
+    ANY = 0xFFFFFFFF,
+}
diff --git a/keymaster/aidl/android/hardware/keymaster/Timestamp.aidl b/keymaster/aidl/android/hardware/keymaster/Timestamp.aidl
new file mode 100644
index 0000000..4b2f108
--- /dev/null
+++ b/keymaster/aidl/android/hardware/keymaster/Timestamp.aidl
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2020 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;
+
+@VintfStability
+parcelable Timestamp {
+    long milliSeconds;
+}