Paper 2026/618

QCAP: A Quantum Canary Address Generation Protocol

Ghazaleh Keshavarzkalhori, Universitat Autònoma de Barcelona
Roger Sala-Mimó, Universitat Autònoma de Barcelona
Jordi Herrera-Joancomartí, Universitat Autònoma de Barcelona
Cristina Pérez-Solà, Universitat Autònoma de Barcelona
Abstract

The advent of quantum computing poses a fundamental threat to classical cryptographic assumptions. While algorithms such as RSA and Elliptic-Curve Cryptography are secure against classical adversaries, they would be efficiently broken by a sufficiently powerful quantum adversary. Yet, despite rapid industrial and academic progress, the timeline for achieving a Cryptographically Relevant Quantum Computer (CRQC) remains uncertain and opaque. In this work, we propose a mechanism to monitor quantum capabilities through economic incentives. We introduce QCAP, a trustless distributed protocol for deploying a quantum canary address alert. QCAP enables the creation of publicly auditable cryptographic challenges whose solutions would reveal the existence of quantum computers capable of breaking the Elliptic Curve Discrete Logarithm problem. The protocol is decentralized, secure, efficient, and verifiable, featuring adjustable difficulty and native Bitcoin compatibility. A proof-of-concept implementation demonstrates the feasibility of QCAP as a Bitcoin-based early-warning system for the emergence of quantum computational power.

Note: updated the abstract

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
Keywords
Quantum computingCanary trapsZero-knowledge proofsBlockchainBitcoin
Contact author(s)
Ghazaleh Keshavarzkalhori @ uab cat
Roger Sala @ uab cat
Jordi Herrera @ uab cat
Cristina Perez @ uab cat
History
2026-04-16: last of 3 revisions
2026-03-30: received
See all versions
Short URL
https://ia.cr/2026/618
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2026/618,
      author = {Ghazaleh Keshavarzkalhori and Roger Sala-Mimó and Jordi Herrera-Joancomartí and Cristina Pérez-Solà},
      title = {{QCAP}: A Quantum Canary Address Generation Protocol},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/618},
      year = {2026},
      url = {https://eprint.iacr.org/2026/618}
}
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