An Identity-Based Mediated Signature Scheme Without Trusted PKG
Xiaofeng Wang, Shangping Wang · 2011
Xiaofeng Wang and Shangping WangSchool of Science, Xi’an university of technology, Xi’an 710048, P.R.ChinaE-mail: [email protected]: ID-based signature, ID-based mediated signature, without trusted PKG, immediate revocation, GDH groupReceived: July 14, 2008Mediated Signature Scheme provides an efficient method for fast revocation of a user’s identity in identity(ID)-based cryptosystems. The only ID-based mediated signature scheme was proposed by Cheng et al.from bilinear pairing in [8]. Unfortunately, their scheme has an inherent flaw that the PKG is fully capableto generate a valid mediated signature of some message on behalf of its signers by only utilizing thepublic information of the system. In this paper, an efficient ID-based mediated signature scheme withouttrusted PKG is proposed. Compared with the scheme [8], the proposed scheme has other property besidesachieving immediate revocation of a signer’s ID. That is, proposed scheme is ID-based, but without anyassumption of pre-fixed trusted relationship between users and PKG, which effectively solves the problemthat exists in some existing ID-based public key cryptosystems in which a trusted PKG and key escrow areneeded.Povzetek: Predstavljena je metoda elektronskega podpisovanja.