diff --git a/binder/android/os/IVold.aidl b/binder/android/os/IVold.aidl
index dfccc00..d37697b 100644
--- a/binder/android/os/IVold.aidl
+++ b/binder/android/os/IVold.aidl
@@ -91,10 +91,10 @@
     void createUserStorageKeys(int userId, boolean ephemeral);
     void destroyUserStorageKeys(int userId);
 
-    void setCeStorageProtection(int userId, @utf8InCpp String secret);
+    void setCeStorageProtection(int userId, in byte[] secret);
 
     int[] getUnlockedUsers();
-    void unlockCeStorage(int userId, @utf8InCpp String secret);
+    void unlockCeStorage(int userId, in byte[] secret);
     void lockCeStorage(int userId);
 
     void prepareUserStorage(@nullable @utf8InCpp String uuid, int userId, int storageFlags);