Pay-TV system with strong privacy and non-repudiation protection

Current pay-TV systems enable service providers to acquire personal data easily, e.g. the customers' TV-watching habits, which can make customers uncomfortable or cause them inconvenience. Although many privacy protection schemes have been proposed, they only protect customer privacy from abuse by outsiders, not the service providers. This paper develops a new conditional access system (CAS) mechanism - "e-ticket" - for pay-TV systems to protect customer privacy from abuse by both outsiders and providers, while protecting both the customers and the providers against double-spending, loss, misuse, and/or stealing of the e-ticket. This article also demonstrates that the combination of the partial blind digital signature and anonymous digital signature makes pay-TV systems more robust and fairer than before.