diff --git a/keystore/Keymaster4.cpp b/keystore/Keymaster4.cpp
new file mode 100644
index 0000000..3edfb53
--- /dev/null
+++ b/keystore/Keymaster4.cpp
@@ -0,0 +1,39 @@
+/*
+**
+** Copyright 2017, 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.
+*/
+#include "Keymaster4.h"
+
+#include <android-base/logging.h>
+
+namespace keystore {
+
+void Keymaster4::getVersionIfNeeded() {
+    if (haveVersion_) return;
+
+    auto rc = dev_->getHardwareInfo([&](SecurityLevel securityLevel, auto...) {
+        securityLevel_ = securityLevel;
+        haveVersion_ = true;
+    });
+
+    CHECK(rc.isOk()) << "Got error " << rc.description() << " trying to get hardware info";
+}
+
+Keymaster::VersionResult Keymaster4::halVersion() {
+    getVersionIfNeeded();
+    return {ErrorCode::OK, halMajorVersion(), securityLevel_, true};
+}
+
+}  // namespace keystore