Paper 2021/032

Experimental relativistic zero-knowledge proofs

Pouriya Alikhani, Nicolas Brunner, Claude Crépeau, Sébastien Designolle, Raphaël Houlmann, Weixu Shi, and Hugo Zbinden


Protecting secrets is a key challenge in our contemporary information-based era. In common situations, however, revealing secrets appears unavoidable, for instance, when identifying oneself in a bank to retrieve money. In turn, this may have highly undesirable consequences in the unlikely, yet not unrealistic, case where the bank’s security gets compromised. This naturally raises the question of whether disclosing secrets is fundamentally necessary for identifying oneself, or more generally for proving a statement to be correct. Developments in computer science provide an elegant solution via the concept of zero-knowledge proofs: a prover can convince a verifier of the validity of a certain statement without facilitating the elaboration of a proof at all. In this work, we report the experimental realisation of such a zero-knowledge protocol involving two separated verifier-prover pairs. Security is enforced via the physical principle of special relativity, and no computational assumption (such as the existence of one-way functions) is required. Our implementation exclusively relies on off-the-shelf equipment and works at both short (60 m) and long distances (400 m) in about one second. This demonstrates the practical potential of multi-prover zero-knowledge protocols, promising for identification tasks and blockchain-based applications such as cryptocurrencies or smart contracts.

Note: To be submitted to Nature.

Available format(s)
Cryptographic protocols
Publication info
Preprint. MINOR revision.
Zero-KnowledgeSpecial Relativity3-colorability
Contact author(s)
crepeau @ cs mcgill ca
2021-01-12: received
Short URL
Creative Commons Attribution


      author = {Pouriya Alikhani and Nicolas Brunner and Claude Crépeau and Sébastien Designolle and Raphaël Houlmann and Weixu Shi and Hugo Zbinden},
      title = {Experimental relativistic zero-knowledge proofs},
      howpublished = {Cryptology ePrint Archive, Paper 2021/032},
      year = {2021},
      note = {\url{}},
      url = {}
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