diff --git a/KeyUtil.h b/KeyUtil.h
index d4c97b9..412b0ae 100644
--- a/KeyUtil.h
+++ b/KeyUtil.h
@@ -17,32 +17,21 @@
 #ifndef ANDROID_VOLD_KEYUTIL_H
 #define ANDROID_VOLD_KEYUTIL_H
 
+#include "KeyBuffer.h"
+
 #include <string>
+#include <memory>
 
 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 randomKey(KeyBuffer* key);
+bool installKey(const KeyBuffer& 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);
 bool retrieveKey(bool create_if_absent, const std::string& key_path,
-                 const std::string& tmp_path, std::string* key);
+                 const std::string& tmp_path, KeyBuffer* key);
 
 }  // namespace vold
 }  // namespace android