A New Design of Oblivious Transfer for Private Information Retrieval

In a t-out-n oblivious transfer, the receiver can only receive t messages out of n messages sent by the sender; and the sender has no idea about which ones have been received. Majority of the existing of previous efficient oblivious transfer schemes require t calls of 1-out-n oblivious transfer to construct the t-out-n oblivious transfer. Its computational requirements and bandwidth consumption are quite demanding. Therefore, to guarantee the quality of electronic commercial service, an efficient t-out-n oblivious transfer scheme is urgently desired. Based on the RSA, we propose a new t-out-n oblivious transfer protocol for private information retrieval in this paper. In our method, only several modular multiplications and t hash functions are performed by a user (receiver) to obtain t messages. It is very suitable for the limited computation capacities of receivers such as smart cards or mobile units. Key words: Private information retrieval, security, RS