Secure offline payment system

摘要

A method for providing secure offline payments comprises an account system that communicates a signed balance certificate to a user device. The system accesses the user's account, determines the available unlocked funds, creates and signs a balance certificate, and transmits the signed balance certificate to the user device. To complete an offline payment transaction, the user device and a merchant device establish a communication channel. The merchant device transmits a payment request to the user device. A signed withdrawal record and the signed balance certificate are transmitted to the merchant device for verification and completion of the offline payment transaction. The merchant device signs the withdrawal record, transmits it to the user device, and saves it until the merchant device has network access and can transmit the it to the system. The system verifies the withdrawal record and records it in the user's account.