Jessica Sorrell (Theory Seminar)

Oblivious transfer is a cryptographic protocol first introduced by Rabin '81, carried out between two parties: a sender and a receiver. The sender possesses two messages, and the receiver possesses a bit, corresponding to the message it wishes to receive. An oblivious transfer protocol allows the receiver to "request" one of the two messages, without the sender learning which message is being requested, and allows the sender to transfer the correct message to the receiver, without the receiver learning anything about the second message.

 

We present a two-message oblivious transfer protocol achieving statistical sender privacy, based on the RLWE assumption for cyclotomic number fields. This work improves upon prior lattice-based statistically sender-private oblivious transfer protocols by reducing the total communication between parties by a factor O(n log n) for transfer of length O(n) messages.