Practical Quantum Bit Commitment Protocol Based on Quantum Oblivious Transfer

Oblivious transfer (OT) and bit commitment (BC) are two-party cryptographic protocols which play crucial roles in the construction of various cryptographic protocols. We propose three practical quantum cryptographic protocols in this paper. We first construct a practical quantum random oblivious transfer (R-OT) protocol based on the fact that non-orthogonal states cannot be reliably distinguished. Then, we construct a fault-tolerant one-out-of-two oblivious transfer ( O T 1 2 ) protocol based on the quantum R-OT protocol. Afterwards, we propose a quantum bit commitment (QBC) protocol which executes the fault-tolerant O T 1 2 several times. Mayers, Lo and Chau (MLC) no-go theorem proves that QBC protocol cannot be unconditionally secure. However, we find that computing the unitary transformation of no-go theorem attack needs so many resources that it is not realistically implementable. We give a definition of physical security for QBC protocols and prove that the practical QBC we proposed is physically secure and can be implemented in the real world.

Randomized quantum oblivious transfer with application in hacker-resistant computation

OT (Oblivious transfer) is a fundamental primitive in cryptography. But it is well known that in quantum cryptography, unconditionally secure OT is impossible. A variant of OT, i.e. randomized OT, is presented. We then show how to realize this variant in quantum cryptography with some security relaxations, which is inevitable because of the well-known impossible result in quantum cryptography. We also present a new secure computational model, namely HRC (Hacker-Resistant Computation) model. Since on today’s Internet there are more and more hackers and increased cyber threat, knowing how to protect the information and privacy stored on our computer and on cloud servers is very important, even when the computer or server has been breached by hackers. Finally, some interesting applications of the randomized OT variant to HRC are discussed.