Deterministic Relativistic Quantum Bit Commitment

TL;DR

This paper introduces new deterministic quantum bit commitment schemes based on relativistic causality and entanglement monogamy, achieving high security without requiring secret randomness, even in the presence of losses and errors.

Contribution

It presents novel unconditionally secure, deterministic quantum bit commitment protocols leveraging Minkowski causality and entanglement monogamy, with practical advantages in security and implementation.

Findings

Schemes are secure against losses and errors.

Deterministic protocols eliminate need for secret randomness.

Security can be perfect with an additional secret bit.

Abstract

We describe new unconditionally secure bit commitment schemes whose security is based on Minkowski causality and the monogamy of quantum entanglement. We first describe an ideal scheme that is purely deterministic, in the sense that neither party needs to generate any secret randomness at any stage. We also describe a variant that allows the committer to proceed deterministically, requires only local randomness generation from the receiver, and allows the commitment to be verified in the neighbourhood of the unveiling point. We show that these schemes still offer near-perfect security in the presence of losses and errors, which can be made perfect if the committer uses an extra single random secret bit. We discuss scenarios where these advantages are significant.