diff --git a/extend/Tools/Decrypt.php b/extend/Tools/Decrypt.php
index e3a920d4a2fb7ea8aa9d33cfcfbaa21679c63509..92011f1ded93675f49481f29d12da8138de114db 100644
--- a/extend/Tools/Decrypt.php
+++ b/extend/Tools/Decrypt.php
@@ -35,7 +35,7 @@ class Decrypt
                 'encrypt' => $_encrypt,
             ];
             $sha1 = $this->getSHA1($params);
-            if ($sha1 != $postInfo['msg_signature']) {
+            if ($sha1 != $msgSign) {
                 return false;
             }
             $encryptMsg = $this->decrypt($params['encrypt']);