Design of unlinkable transaction protocol for preserving customer privacy

Abstract

Privacy is becoming a serious challenge in computerized environments, especially the Web where many companies constantly attempt to violate the privacy of users. Privacy infringements when companies gather customer information are more likely to occur if the customer lacks control over this process. In general, most of privacy-preserving systems use pseudonyms or employ the Trusted Third Party (TTP) that hides all user information from web servers. However, users may want or need to identify themselves over the net but still retain their activities and profile in private. On the contrary, it is necessary for internet companies to know the user preference for their marketing activities and auditing. It is obviously conflicting between the user privacy protecting and the company``s requirements. In this thesis, we presented the system protocol that provides the customer``s privacy and satisfies business requirements for the digital content transactions. In our approach, the customer reveals his/her. identity information(such as bank account or credit card number) in exchange for a digital content while protecting the privacy. Moreover, the Internet company is also able to obtain customer``s buying pattern or preferences but the customer``s privacy is sufficiently protected by unlinkability between customer identity and profile information. The proposed system is designed with Chaum``s RSA blind signature scheme[13] and operated on the open network as well as anonymity networks.