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One-more Unforgeability of Blind ECDSA (Qin, Cai, Yuen 2021)

Last modified: 2026-10-27

DOI: 10.1007/978-3-030-88428-4_16 · URL: https://eprint.iacr.org/2021/1449

Summary

Gives the first formal security analysis of one-more unforgeability for blind ECDSA, where the issuer signs without seeing the message and the user obtains a standard ECDSA signature. Describes an ROS-style attack (the ECDSA-ROS problem), a generic construction from additively homomorphic encryption plus a ZK proof (about 40x more bandwidth-efficient than prior work), and a proof in a new algebraic bijective random oracle model. Relevant for e-ID because it shows how blind, unlinkable issuance could be retrofitted onto the ECDSA infrastructure already deployed in wallets and secure elements.

Related resources

• Anonymous Credentials from ECDSA (Frigo & shelat 2024) (paper, 2024)
• ZKAttest: Ring and Group Signatures for Existing ECDSA Keys (Faz-Hernández, Ladd, Maram 2022) (paper, 2022)