diff --git a/keystore2/aaid/aaid.hpp b/keystore2/aaid/aaid.hpp
new file mode 100644
index 0000000..9e2c148
--- /dev/null
+++ b/keystore2/aaid/aaid.hpp
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 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.
+ */
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+/**
+ * This is a redefinition of KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE in
+ * system/security/keystore/keystore_attestation_id.h and must be kept in sync.
+ * There is a static assert in aaid.cpp to assure that they are in sync.
+ * We redefine this here to avoid unnecessary build dependencies for
+ * the rust bindgen target.
+ */
+constexpr const size_t KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE = 1024;
+
+extern "C" {
+    /**
+     * Fills the buffer at aaid with the attestation application id of the app uid.
+     * The buffer must be exactly KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE bytes in size.
+     * *aaid_size is set to the number of bytes written to aaid.
+     *
+     * @param uid the uid of the app to retrieve the aaid for.
+     * @param aaid output buffer for the attestation id.
+     * @param aaid_size must be set to the size of the output buffer, which must be exactly
+     *          KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE bytes in size, by the caller. On success
+     *          it is set to the number of bytes written.
+     * @return OK on success.
+     */
+    uint32_t aaid_keystore_attestation_id(uint32_t uid, uint8_t* aaid, size_t* aaid_size);
+}