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Journal of Applied Mathematics
Volume 2014, Article ID 983040, 14 pages
http://dx.doi.org/10.1155/2014/983040
Research Article

An -Hiding Revocable Group Signature Scheme: Group Signatures with the Property of Hiding the Number of Revoked Users

1National Institute of Information and Communications Technology (NICT), 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan
2Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan

Received 11 November 2013; Accepted 14 April 2014; Published 2 June 2014

Academic Editor: Baolin Wang

Copyright © 2014 Keita Emura et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

If there are many displaced workers in a company, then a person who goes for job hunting might not select this company. That is, the number of members who quit is quite negative information. Similarly, in revocable group signature schemes, if one knows (or guesses) the number of revoked users (say ), then one may guess the reason behind such circumstances, and it may lead to harmful rumors. However, no previous revocation procedure can achieve hiding . In this paper, we propose the first revocable group signature scheme, where is kept hidden, which we call -hiding revocable group signature. To handle this property, we newly define the security notion called anonymity with respect to the revocation which guarantees the unlinkability of revoked users.