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  • Open Access

Honest-binding quantum bit commitment from separable operations

Ziad Chaoui and Anna Pappa*

Matteo Rosati

  • *Contact author: ziad.chaoui@tu-berlin.de
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Phys. Rev. A 113, 062401 – Published 1 June, 2026

DOI: https://doi.org/10.1103/58t8-dj5y

Abstract

Bit commitment is a fundamental cryptographic primitive and a cornerstone for numerous two-party cryptographic protocols, including zero-knowledge proofs. However, it has been proven that unconditionally secure bit commitment, both classical and quantum, is impossible. In this work, we demonstrate that imposing a restriction on the committing party to perform only separable operations enables secure quantum bit-commitment schemes. Specifically, we prove that in any perfectly hiding bit-commitment protocol, an honestly committing party limited to separable operations will be detected with high probability if they attempt to alter their commitment. To illustrate our findings, we present an example protocol.

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Phys. Rev. A 113, 062401– Published 1 June, 2026
  • Received 22 December 2025
  • Accepted 5 May 2026
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