Fairness and privacy on pay-per view system for Web-based video service

Zhou-Lam (see Second International Workshop on Practice and Theory in Public Key Cryptography, PKC'99, Kamakura, Japan, p.315-26, 1999) proposed a fair pay-per view (PPV) protocol for Web-based video service. Their protocol allows viewers to freely choose the video programs to view at any time and pay for what they have viewed. However, we have found that their protocol has a security flaw. It can make an attacker free view video programs from the PPV server. Therefore, we design a remedy to withstand the security flaw. Moreover, we develop an efficient fair PPV protocol with additional privacy property. With our protocol, a viewer can assert his/her video-watching on net privacy. The security and performance of the proposed protocol are also examined.