Abstract
Online privacy is an increasingly important problem, as many services are now offered in a digital form. Privacy (or the lack thereof) is of a special concern in subscriptions to large data repositories with heterogeneous information, where the service provider can easily profile its users and sell that information to third parties. In this work we present the design and implementation of a system that closely resembles the current practice of subscriptions to many services such as newspapers, digital libraries, music collections, etc., but at the same time offers anonymous access to the service. As with current practice, in our solution a user subscribes to the service obtaining access to it for a certain period of time, at the end of which the subscription expires.
In our system user access is always anonymous and no two transactions by the same user can be linked together. Moreover, the system assures a high level of protection to the service provider, as a user cannot share her subscription credentials with others without denying herself access to the service. We present experimental results showing that the design of our system results in only small computation overheads, in addition to having very low communication requirements. The main objective of this work is thus to illustrate the practically of integrating anonymity into today's subscription-based services.
