How to Evaluate Contents Popularity over Oblivious Transfer

We consider the question of how to evaluate popularity of digital contents or goods over a distribution service using Oblivious Transfer (OT) protocol. The popularity of served content is the most important marketing data for data mining and analysis, but the idea of oblivious transfer is too privacy-protecting because the service provider cannot obtain any information about a user´s queries. In this paper, our goal is to construct an OT protocol that 1) allows a user to purchase digital content from the service provider without the provider finding out what content the user is buying, 2) prevents the user find out about any information of other contents that s/he does not ask about, and 3) enables the provider to evaluate the popularity of each piece of content. In this paper, the popularity of each piece of content is defined as the number of users who retrieve it.