School of Computer and Information Science, Security Research Centre, Edith Cowan University, Perth, Western Australia
In this paper, we consider a scenario where there are a group of clients and a database server, and a client wishes to query the database, but does not want to reveal her or his query to the server. Current solutions for this problem are based on oblivious transfer, which usually requires high communication overhead. To reduce the communication overhead, we propose three k-anonymous private query protocols. Our first protocol is based on blind signature, where the server cannot determine the identity of the querying client from the group. Our second protocol is based on k-anonymous oblivious transfer, where the server cannot tell which record the querying client wants from k records. Our third protocol is a combination of the first and second protocols. Our protocols can achieve k-anonymity and are practical in many real-life applications.