Cryptology ePrint Archive: Report 2014/278

Stronger Security Notions for Decentralized Traceable Attribute-Based Signatures and More Efficient Constructions

Essam Ghadafi

Abstract: Traceable attribute-based signatures extend standard attribute-based signatures by granting a designated tracing authority the power to revoke the anonymity of signatures by revealing who signed them. Such a feature is important in deterring abuse and enforcing accountability.

In this work, we revisit the notion of Decentralized Traceable Attribute-Based Signatures (DTABS) introduced by El Kaafarani et al. (CT-RSA 2014) and improve the state-of-the-art in two directions: Firstly, we provide a new stronger security model which circumvents some shortcomings in existing models. Our model minimizes the trust placed in attribute authorities and hence provides, among other things, a stronger definition for non-frameability. In addition, unlike previous models, our model captures the notion of tracing soundness which ensures that even if all parties in the system are fully corrupt, no one but the user who produced the signature could claim authorship of the signature. Secondly, we provide a generic construction that is secure w.r.t.\ our strong security model and show two example instantiations in the standard model which are much more efficient than existing constructions (secure under weaker security definitions).

Category / Keywords: public-key cryptography / Attribute-based signatures, security definitions, traceability, standard model.

Date: received 22 Apr 2014, last revised 22 Apr 2014

Contact author: eg6947 at googlemail com

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Version: 20140424:222430 (All versions of this report)

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