Robust Relativistic Bit Commitment

Abstract

Relativistic cryptography exploits the fact that no information can travel faster than the speed of light in order to obtain security guarantees that cannot be achieved from the laws of quantum mechanics alone. Recently, Lunghi et al [Phys. Rev. Lett. 2015] presented a bit commitment scheme where each party uses two agents that exchange classical information in a synchronized fashion, and that is both hiding and binding. A caveat is that the commitment time is intrinsically limited by the spatial configuration of the players, and increasing this time requires the agents to exchange messages during the whole duration of the protocol. While such a solution remains computationally attractive, its practicality is severely limited in realistic settings since all communication must remain perfectly synchronized at all times. In this work, we introduce a robust protocol for relativistic bit commitment that tolerates failures of the classical communication network. This is done by adding a third agent to both parties. Our scheme provides a quadratic improvement in terms of expected sustain time compared to the original protocol, while retaining the same level of security.

arXiv comment22 pages, 1 figure

References in corpus (13)

• Unconditionally secure quantum bit commitment is impossible
• Is Quantum Bit Commitment Really Possible?
• Unconditionally Secure Bit Commitment
• Unconditionally Secure Bit Commitment by Transmitting Measurement Outcomes
• Quantum Tagging: Authenticating Location via Quantum Information and Relativistic Signalling Constraints
• Experimental bit commitment based on quantum communication and special relativity
• Unconditionally Secure Bit Commitment with Flying Qudits
• Position-Based Quantum Cryptography: Impossibility and Constructions
• Insecurity of position-based quantum cryptography protocols against entanglement attacks
• Practical relativistic bit commitment
• Secure bit commitment from relativistic constraints
• 24-Hour Relativistic Bit Commitment
• Arbitrarily long relativistic bit commitment