A Non-Interactive Quantum Bit Commitment Scheme that Exploits the Computational Hardness of Quantum State Distinction

TL;DR

This paper introduces a non-interactive quantum bit commitment protocol that relies on the computational hardness of distinguishing quantum states, offering a potentially simpler assumption than previous protocols based on quantum one-way functions.

Contribution

It presents a novel quantum bit commitment scheme that is non-interactive, does not require shared randomness, and is based on the hardness of quantum state distinction, a weaker assumption than prior work.

Findings

Achieves computational concealing and statistical binding.

Relies on the hardness of the graph automorphism problem.

Simplifies assumptions compared to earlier protocols.

Abstract

We propose an efficient quantum protocol performing quantum bit commitment, which is a simple cryptographic primitive involved with two parties, called a committer and a verifier. Our protocol is non-interactive, uses no supplemental shared information, and achieves computational concealing and statistical binding under a natural complexity-theoretical assumption. An earlier protocol in the literature relies on the existence of an efficient quantum one-way function. Our protocol, on the contrary, exploits a seemingly weaker assumption on computational difficulty of distinguishing two specific ensembles of reduced quantum states. This assumption is guaranteed by, for example, computational hardness of solving the graph automorphism problem efficiently on a quantum computer.