Anonymity is a necessary property for postpaid micropayment schemes to protect the customers' privacy. Customers also gain the shopping convenience in postpaid way. In 2006, Huang first proposed an anonymous postpaid micropayment scheme that needs a trusted bank to provide customers' anonymity and finance services. However, the building and maintenance of trusted banks causes the impracticality of Huang's scheme. To remove trusted banks, a postpaid micropayment scheme with revocable customers' anonymity is proposed. Our scheme not only overcomes the impractical frauds in Huang's scheme but also is more efficient and practical than Huang's scheme. Moreover, our scheme is the first micropayment scheme adopting concurrent signature schemes to provide customer anonymity.
2007 NCS 中華民國九十六年全國計算機會議大會論文集=Proceedings of 2007 National Computer Symposium，13頁