A Universal Blinder: One-round Blind Signatures from FHE

Dan Boneh; Jaehyung Kim

Paper 2026/574

A Universal Blinder: One-round Blind Signatures from FHE

Dan Boneh

, Stanford University

Jaehyung Kim

, Stanford University

Abstract

We construct compilers that convert any secure signature scheme into a single-round blind signature scheme. An important property of the construction is that the final blind signature has exactly the same format as the underlying signature scheme, making the blind signature scheme backwards compatible with the underlying scheme. Our compilers make use of (two-key) fully homomorphic encryption and zero-knowledge proofs to ensure unforgeability and blindness of the final scheme. We present three compilers where the main differences is which party does the bulk of the work: the client, the signer, or both. Along the way we introduce a new notion of verifiable FHE that we call committed verifiable FHE, where the verifier does not see the circuit in the clear.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
Keywords: Blind Signature Fully Homomorphic Encryption
Contact author(s): dabo @ cs stanford edu
jaehk @ cs stanford edu
History: 2026-03-23: approved; 2026-03-23: received; See all versions
Short URL: https://ia.cr/2026/574
License: CC BY

BibTeX

@misc{cryptoeprint:2026/574,
      author = {Dan Boneh and Jaehyung Kim},
      title = {A Universal Blinder: One-round Blind Signatures from {FHE}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/574},
      year = {2026},
      url = {https://eprint.iacr.org/2026/574}
}