Unconditionally secure commitment in position-based quantum cryptography

Abstract

A new commitment scheme based on position-verification and non-local quantum correlations is presented here for the first time in literature. The only credential for unconditional security is the position of committer and non-local correlations generated; neither receiver has any pre-shared data with the committer nor does receiver require trusted and authenticated quantum/classical channels between him and the committer. In the proposed scheme, receiver trusts the commitment only if the scheme itself verifies position of the committer and validates her commitment through non-local quantum correlations in a single round. The position-based commitment scheme bounds committer to reveal valid commitment within allocated time and guarantees that the receiver will not be able to get information about commitment unless committer reveals. The scheme works for the commitment of both bits and qubits and is equally secure against committer/receiver as well as against any third party who may have interests in destroying the commitment. Our proposed scheme is unconditionally secure in general and evades Mayers and Lo-Chau attacks in particular.

Two Quantum Protocols for Oblivious Set-member Decision Problem

“…the integer factorization or the discrete logarithm problems, may be fragile in the future with the presence of quantum computers. On the other hand, fortunately, this difficulty can be overcome by quantum cryptography 3 4 , where the security is guaranteed by physical principles. Since Bennett and Brassard presented the first quantum key distribution protocol 5 , quantum cryptography has been widely studied and rapidly developed.…”