Cryptology ePrint Archive: Report 2018/1115

Short Group Signature in the Standard Model

Remi Clarisse and Olivier Sanders

Abstract: Group signature is a central tool for privacy-preserving protocols, ensuring authentication, anonymity and accountability. It has been massively used in cryptography, either directly or through variants such as direct anonymous attestations. However it remains a complex tool, especially in the standard model where each of its building blocks is quite costly to instantiate.

In this work, we propose a new group signature scheme proven secure in the standard model which significantly decreases the complexity with respect to the state-of-the-art. More specifically, we halve both the size and the computational cost compared to the most efficient alternative in the standard model. Moreover, our construction is also competitive against the most efficient ones in the random oracle model, thus closing the traditional efficiency gap between these two models.

Our construction is based on a tailored combination of two popular signatures, which avoids the explicit use of encryption schemes or zero-knowledge proofs. It is flexible enough to achieve security in different models and is thus suitable for most contexts.

Category / Keywords: cryptographic protocols / group signature, standard model

Date: received 16 Nov 2018, last revised 13 Dec 2018

Contact author: olivier sanders at orange com

Available format(s): PDF | BibTeX Citation

Version: 20181213:133655 (All versions of this report)

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