Research Abstracts - 2006

Practical Group Signatures Without Random Oracles

Giuseppe Ateniese, Jan Camenisch, Susan Hohenberger & Breno de Medeiros

Abstract.

We present the first constant-size group signature scheme that is provably secure in the standard model without the need for relaxed setup assumptions. The proof follows a new ideal/real-world definition of security for group signatures that encapsulates all the standard properties of unforgeability, anonymity, unlinkability, and exculpability. Security of our constructions require certain cryptographic assumptions, namely the Strong LRSW, EDH, and Strong SXDH assumptions. Evidence for the newly introduced assumptions is provided by proving them secure in the generic group model.

Our signatures are very short (independent of the number of group members), costing roughly 35 percent more bits than the shortest known group signatures *with* random oracles due to Boneh, Boyen, and Shacham.

Funding.

Susan conducted this work while at IBM Zurich Research, Switzerland.

References:

[1] Giuseppe Ateniese (Johns Hopkins), Jan Camenisch (IBM Zurich Research), Susan Hohenberger and Breno de Medeiros (Florida State). Practical Group Signatures without Random Oracles. In submission. Full version on eprint.