Cryptology ePrint Archive: Report 2018/874

Enhanced Security of Attribute-Based Signatures

Johannes Blömer and Fabian Eidens and Jakob Juhnke

Abstract: Despite the recent advances in attribute-based signatures (ABS), no schemes have yet been considered under a strong privacy definition. We enhance the security of ABS by presenting a strengthened simulation-based privacy definition and the first attribute-based signature functionality in the framework of universal composability (UC). Additionally, we show that the UC definition is equivalent to our strengthened experiment-based security definitions.

To achieve this we rely on a general unforgeability and a simulation-based privacy definition that is stronger than standard indistinguishability-based privacy. Further, we show that two extant concrete ABS constructions satisfy this simulation-based privacy definition and are therefore UC secure. The two concrete constructions are the schemes by Sakai et al. (PKC'16) and by Maji et al. (CT-RSA'11). Additionally, we identify the common feature that allows these schemes to meet our privacy definition, giving us further insights into the security requirements of ABS.

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Original Publication (with minor differences): CANS 2018

Date: received 18 Sep 2018, last revised 28 Sep 2018

Contact author: feidens at mail uni-paderborn de

Available format(s): PDF | BibTeX Citation

Version: 20180928:170553 (All versions of this report)

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