本論文探討如何在一複合式銀行(multiple bank)架構的環境下建構一安全且有效的電子現金(electronic cash)付費機制,我們延伸Paterson植基於橢圓曲線密碼系統(elliptic curve cryptosystems)的身份碼簽章(identity-based signatures),並與盲簽(blind signatures)技術結合發展出一群體盲目簽章(group blind signatures)方法,並將其應用於電子現金付費系統中,使得消費者可以匿名的消費,而商家只需用一把群體公開金鑰即可驗證不同銀行所發行的匿名電子現金的合法性。此外,當發生重複消費問題時,銀行可以在可信任機構的幫助下追查出消費者的身份。
In this paper, a group blind signature scheme is proposed and applied on multiple-bank electronic payment systems. The scheme is based on bilinear pairings of elliptic curve and Paterson’s identity-based signature to make a payer to spend his electronic cash anonymously, and any participant in the electronic payment system only need to store one bank group public key without any public key certificate. Such a key is used to verify the legitimacy of any cash issued by any bank. Moreover, a trusted arbiter can find out the real identity of cash owner who spends the cash twice, called as double-spending.