Cryptology ePrint Archive: Report 2022/190

Short-lived zero-knowledge proofs and signatures

Arasu Arun and Joseph Bonneau and Jeremy Clark

Abstract: We introduce the short-lived proof, a non-interactive proof of knowledge with a novel feature: after a specified period of time, the proof is no longer convincing. This time-delayed loss of soundness happens "naturally" without further involvement from the prover or any third party. We propose formal definitions for short-lived proofs as well as the special case of short-lived signatures. We show several practical constructions built using verifiable delay functions (VDFs). The key idea in our approach is to allow any party to forge any proof by executing a large sequential computation. Some constructions achieve a stronger property called reusable forgeability in which one sequential computation allows forging an arbitrary number of proofs of different statements. Our work also introduces two novel types of VDFs, re-randomizable VDFs and zero-knowledge VDFs, which may be of independent interest.

Category / Keywords: cryptographic protocols / zero knowledge, RSA, digital signatures, VDFs

Date: received 17 Feb 2022

Contact author: jbonneau at gmail com, aa7977 at nyu edu, j clark at concordia ca

Available format(s): PDF | BibTeX Citation

Version: 20220220:203749 (All versions of this report)

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