A brief review on the impossibility of quantum bit commitment

TL;DR

This paper reviews the fundamental impossibility of unconditionally secure quantum bit commitment, highlighting the theoretical proof and recent attempts to circumvent this limitation in quantum cryptography.

Contribution

It provides a concise overview of the impossibility theorem for quantum bit commitment and discusses recent efforts to overcome this fundamental limitation.

Findings

Unconditionally secure quantum bit commitment is proven impossible.

The review covers the general impossibility theorem and recent bypass attempts.

Historical development of quantum bit commitment protocols is summarized.

Abstract

The desire to obtain an unconditionally secure bit commitment protocol in quantum cryptography was expressed for the first time thirteen years ago. Bit commitment is sufficient in quantum cryptography to realize a variety of applications with unconditional security. In 1993, a quantum bit commitment protocol was proposed together with a security proof. However, a basic flaw in the protocol was discovered by Mayers in 1995 and subsequently by Lo and Chau. Later the result was generalized by Mayers who showed that unconditionally secure bit commitment is impossible. A brief review on quantum bit commitment which focuses on the general impossibility theorem and on recent attempts to bypass this result is provided.