Quantum oblivious transfer based on unambiguous set discrimination

For the first time we investigate cryptographic applications of unambiguous set discrimination in quantum oblivious transfer. In particular, using techniques for unambiguous set discrimination, we present a novel quantum protocol for all-or-nothing oblivious transfer (OT). Using the same technique, we further propose an efficient and economical quantum protocol for one-out-of-two OT. The receiver performs only Bell-state measurements (BSM) to attain the goal of all-or-nothing OT or one-out-of-two OT. Moreover in the second protocol, all the conclusive and inconclusive results are useful to determine the sender's secret bits so that the qubit efficiency of the protocol is improved to 100%. Decoy-state-technology-like detection method ensures the security of the proposed protocols.