diff --git a/apps/user_ldap/lib/Connection.php b/apps/user_ldap/lib/Connection.php
index 5105c12a22fcd..ab1ab11de4706 100644
--- a/apps/user_ldap/lib/Connection.php
+++ b/apps/user_ldap/lib/Connection.php
@@ -218,7 +218,7 @@ private function getCacheKey($key) {
 		if(is_null($key)) {
 			return $prefix;
 		}
-		return $prefix.md5($key);
+		return $prefix.hash('sha256', $key);
 	}
 
 	/**
diff --git a/apps/user_ldap/lib/Proxy.php b/apps/user_ldap/lib/Proxy.php
index dc8c6fc77cc61..ab5434f9fe5fd 100644
--- a/apps/user_ldap/lib/Proxy.php
+++ b/apps/user_ldap/lib/Proxy.php
@@ -163,7 +163,7 @@ private function getCacheKey($key) {
 		if($key === null) {
 			return $prefix;
 		}
-		return $prefix.md5($key);
+		return $prefix.hash('sha256', $key);
 	}
 
 	/**