Blind ECDSA from the ECDSA Assumption

Jules Maire; Alan Pulval-Dady

Paper 2025/1827

Blind ECDSA from the ECDSA Assumption

Jules Maire, DIENS, Ecole normale supérieure, PSL University, CNRS, INRIA, Paris, France

Alan Pulval-Dady, Research Institute CODE, Universität der Bundeswehr

Abstract

Blind signatures have become a cornerstone for privacy-sensitive applications such as digital cash, anonymous credentials, and electronic voting. The elliptic curve variant of the Digital Signature Algorithm (ECDSA) is widely adopted due to its efficiency in resource-constrained environments, such as mobile devices and blockchain systems. Building blind ECDSA is hence a natural goal. One presents the first such construction relying solely on the ECDSA assumption. Despite the inherent complexities in integrating blindness with ECDSA, we design a protocol that ensures both unforgeability and blindness without introducing new computational assumptions and ensuring concurrent security. It involves zero-knowledge proofs based on the MPC-in-the-head paradigm for complex statements combining relations on encrypted elliptic curve points, their coordinates, and discrete logarithms.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published by the IACR in CIC 2025
Keywords: Blind Signature ECDSA MPC-in-the-Head
Contact author(s): jules maire @ ens fr
alan pulval-dady @ unibw de
History: 2025-10-08: approved; 2025-10-03: received; See all versions
Short URL: https://ia.cr/2025/1827
License: CC BY

BibTeX

@misc{cryptoeprint:2025/1827,
      author = {Jules Maire and Alan Pulval-Dady},
      title = {Blind {ECDSA} from the {ECDSA} Assumption},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1827},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1827}
}