—As a variation of ordinary digital signature scheme, a proxy signature scheme able a proxy signer to sign messages on behalf of the original signer. Proxy multi-signature is an extension of the basic proxy signature primitive and permits two or more entities to delegate their signing capabilities to the same other entity. In proxy multi-signature, many original signers can delegate their signing power to a proxy signer in such a way that the proxy signer can sign any message on behalf of original signers. In blind signature, the signer cannot make a linkage between the blind signature and the identity of the requester. Proxy blind multi-signature is the combination of proxy multi-signature and blind signature. Recently, Lu et al
. presented a proxy blind multi-signature scheme which did not need a secure channel. However, in this paper, we show that Lu et al
.'s scheme does not satisfy the unforgeability and also shown that their scheme is not secure against the original signer's forgery attack and the proxy signer's forgery attacks.
—Blind signature, proxy-multi signature, proxy blind multi signature, security.
The authors are with the School of Studies in Mathematics Pt. Ravishankar Shukla University, Raipur (C.G.), India (e-mail: email@example.com, firstname.lastname@example.org).
Cite:Swati Verma and Birendra Kumar Sharma, "Cryptanalysis of Lu et al.'s Proxy Blind Multi Signature Scheme," International Journal of Computer Theory and Engineering vol. 5, no. 5, pp. 820-822, 2013.