diff --git a/KeyStorage.h b/KeyStorage.h
index 786e5b4..6aaf3ad 100644
--- a/KeyStorage.h
+++ b/KeyStorage.h
@@ -61,7 +61,8 @@
                         const KeyAuthentication& auth, const KeyBuffer& key);
 
 // Retrieve the key from the named directory.
-bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffer* key);
+bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffer* key,
+                 bool keepOld = false);
 
 // Securely destroy the key stored in the named directory and delete the directory.
 bool destroyKey(const std::string& dir);