diff --git a/KeyUtil.h b/KeyUtil.h
new file mode 100644
index 0000000..56cb189
--- /dev/null
+++ b/KeyUtil.h
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+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_VOLD_KEYUTIL_H
+#define ANDROID_VOLD_KEYUTIL_H
+
+#include <string>
+
+namespace android {
+namespace vold {
+
+// ext4enc:TODO get this const from somewhere good
+const int EXT4_KEY_DESCRIPTOR_SIZE = 8;
+
+// ext4enc:TODO Include structure from somewhere sensible
+// MUST be in sync with ext4_crypto.c in kernel
+constexpr int EXT4_ENCRYPTION_MODE_AES_256_XTS = 1;
+constexpr int EXT4_AES_256_XTS_KEY_SIZE = 64;
+constexpr int EXT4_MAX_KEY_SIZE = 64;
+struct ext4_encryption_key {
+    uint32_t mode;
+    char raw[EXT4_MAX_KEY_SIZE];
+    uint32_t size;
+};
+
+bool randomKey(std::string* key);
+bool installKey(const std::string& key, std::string* raw_ref);
+bool evictKey(const std::string& raw_ref);
+bool retrieveAndInstallKey(bool create_if_absent, const std::string& key_path,
+                           const std::string& tmp_path, std::string* key_ref);
+
+}  // namespace vold
+}  // namespace android
+
+#endif