Processing certificate of authorization with watermark in security

We propose the safe treatment of the certificate of authorization in this article. We insert the watermark in the certificate of authorization. Both of the owner and grantee keep the certificate of authorization. We encrypt the file of the certificate of authorization and watermark with different key to produce the file of cipher text. Both of the owner and grantee keep their files. When both sides want to confirm, we use their keys to decrypt both files. If the certificate of authorization and watermark are the same, then they are correct. The step that the certificate of authorization is encrypted and decrypted will be safer.