Unconditionally secure commitment in position-based quantum cryptography

TL;DR

This paper introduces a novel position-based quantum commitment scheme that guarantees unconditional security using position verification and non-local quantum correlations, without pre-shared data or trusted channels.

Contribution

It presents the first position-based quantum commitment scheme that is unconditionally secure and resistant to known quantum attacks like Mayers and Lo-Chau.

Findings

Scheme works for both bits and qubits.

Guarantees security against all parties including third parties.

Validates commitment through position verification and quantum correlations.

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.