Algebraic Zero Knowledge Contingent Payment

Javier Gomez-Martinez; Dimitrios Vasilopoulos; Pedro Moreno-Sanchez; Dario Fiore

Paper 2024/1930

Algebraic Zero Knowledge Contingent Payment

Javier Gomez-Martinez

, Universidad Politécnica de Madrid, IMDEA Software Institute

Dimitrios Vasilopoulos

, Independent Researcher

Pedro Moreno-Sanchez

, IMDEA Software Institute, VISA Research, Max Planck Institute for Security and Privacy

Dario Fiore

, IMDEA Software Institute

Abstract

In this work, we introduce Modular Algebraic Proof Contingent Payment (MAPCP), a novel zero-knowledge contingent payment (ZKCP) construction. Unlike previous approaches, MAPCP is the first that simultaneously avoids using zk-SNARKs as the tool for zero-knowledge proofs and HTLC contracts to atomically exchange a secret for a payment. As a result, MAPCP sidesteps the common reference string (crs) creation problem and is compatible with virtually any cryptocurrency, even those with limited or no smart contract support. Moreover, MAPCP contributes to fungibility, as its payment transactions blend seamlessly with standard cryptocurrency payments. We analyze the security of MAPCP and demonstrate its atomicity, meaning that, (i) the buyer gets the digital product after the payment is published in the blockchain (buyer security); and (ii) the seller receives the payment if the buyer gets access to the digital product (seller security). Moreover, we present a construction of MAPCP in a use case where a customer pays a notary in exchange for a document signature.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published elsewhere. Major revision. International Conference on Applied Cryptography and Network Security (ACNS 2025)
Keywords: Zero Knowledge Contingent Payment Blockchain Zero Knowledge Proof
Contact author(s): javier gomez @ imdea org
vasilopo @ eurecom fr
pedro moreno @ imdea org
dario fiore @ imdea org
History: 2024-11-29: approved; 2024-11-28: received; See all versions
Short URL: https://ia.cr/2024/1930
License: CC BY

BibTeX

@misc{cryptoeprint:2024/1930,
      author = {Javier Gomez-Martinez and Dimitrios Vasilopoulos and Pedro Moreno-Sanchez and Dario Fiore},
      title = {Algebraic Zero Knowledge Contingent Payment},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/1930},
      year = {2024},
      url = {https://eprint.iacr.org/2024/1930}
}