diff --git a/mtkclient/Library/cryptutils.py b/mtkclient/Library/cryptutils.py
index e820cf7..70ce3f3 100755
--- a/mtkclient/Library/cryptutils.py
+++ b/mtkclient/Library/cryptutils.py
@@ -306,6 +306,7 @@ class cryptutils:
                 ciphertext = cipher.encrypt(data)
                 return ciphertext
 
+        @staticmethod
         def aes_cmac_verify(key, plain, compare):
             ctx = CMAC.new(key, ciphermod=AES)
             ctx.update(plain)