Cryptology ePrint Archive: Report 2017/682

Conditional Blind Signatures

Alexandros Zacharakis and Panagiotis Grontas and Aris Pagourtzis

Abstract: We propose a novel cryptographic primitive called conditional blind signatures. Our primitive allows a user to request blind signatures on messages of her choice. The signer has a secret Boolean input which determines if the supplied signature is valid or not. The user should not be able to distinguish between valid and invalid signatures. A designated verifier, however, can tell which signatures verify correctly, and is in fact the only entity who can learn the secret input associated with the (unblinded) signed message. We instantiate our primitive as an extension of the Okamoto-Schnorr blind signature scheme and provide variations to fit different usage scenarios. Finally, we analyze and prove the security properties of the new scheme and explore potential applications

Category / Keywords: digital signatures, blind signatures, designated verifier signatures

Original Publication (with minor differences): 7th International Conference on Algebraic Informatics, June 25-28, 2017, Kalamata, Greece

Date: received 7 Jul 2017, last revised 30 Nov 2017

Contact author: pgrontas at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20171130:141140 (All versions of this report)

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