Owing to the explosive growth of the Internet, various electronic payment systems have been studied and suggested. Especially, the security of electronic payment protocols is of interest to researchers in academia and industry. However, the current electronic cash protocols are not offering security of the user's information trufully. The BCY protocols(Beller.,Chang.and Yacov.) is an electronic commerce protocol using certificate in wireless network. The core of BCY is a set of electronic transactions that reflect common trading activities such as purchasing goods or depositing funds. We use FDR(Failure Divergence Refinements) to verify BCY protocols. Our aim in this paper is to design a practical electronic payment protocol which is secure in wireless circumstance.