Title: VLR group signatures with indisputable exculpability and efficient revocation

Authors: Liqun Chen; Jiangtao Li

Addresses: HP Labs, Long Down Avenue, Stoke Gifford, Bristol, BS34 8QZ, UK. ' Intel Labs, Intel Corporation, 2111 NE 25th Ave, Hillsboro, OR 97124, USA

Abstract: Group signatures (GSs) have been studied for two decades and have wide applications. In 2004, Boneh and Shacham formalised the concept of a GS scheme with verifier-local revocation (VLR), where a revocation list is distributed only to verifiers and signers who are not involved in the revocation process. Most of the existing VLR GS schemes do not satisfy exculpability (i.e., neither group members nor group issuers can produce signatures on behalf of other members) without fully trusted issuers or largely increased cost. In this paper, we propose a modification to this GS definition by adding a dispute process that can achieve exculpability with a low cost. We propose a concrete scheme under this new definition. Our scheme is more efficient than previous ones, both with and without exculpability. We also turn this scheme into a conventional VLR GS scheme supporting exculpability, which trade-off the dispute process with less efficient verification/opening processes.

Keywords: group signatures; trusted computing; privacy; anonymity; verifier-local revocation; VLR; trust; exculpability.

DOI: 10.1504/IJIPSI.2012.046130

International Journal of Information Privacy, Security and Integrity, 2012 Vol.1 No.2/3, pp.129 - 159

Available online: 21 Mar 2012 *

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