diff --git a/classes/core_jwt_manager.php b/classes/core_jwt_manager.php
index eb6a114..0fd08ea 100644
--- a/classes/core_jwt_manager.php
+++ b/classes/core_jwt_manager.php
@@ -19,6 +19,7 @@ namespace auth_jwt;
 require_once(__DIR__ . '/../vendor/autoload.php');
 
 use \Firebase\JWT\JWT;
+use \Firebase\JWT\Key;
 
 /**
  * Key manager class.
@@ -96,7 +97,7 @@ class core_jwt_manager
         $secret = $this->config->jwtsecret;
 
         try {
-            $decoded = JWT::decode($keyvalue, $secret);
+            $decoded = JWT::decode($keyvalue, new Key($secret, 'HS256'));
         } catch (\Exception $e) {
             throw new \moodle_exception('invalidkey');
         }