Forgeability attack of two special signature schemes

Abstract

Unforgeabilty is a primitive property of a secure digital signature. As two extensions of digital signature, proxy signature and certificateles blind signature play an important role in the sensitive transmission. In this work, we analyze the security of two signature schemes, one is the certificateless proxy blind signature scheme[6] which was proposed by Tso et al in NSS2010, the other is an efficient proxy signature scheme[8] which was proposed by Hu et al in NSWCTC 2010. Then, we show that the two schemes were insecure, meanwhile, we also show that Tso et al's basic certificateless proxy signature is insecure. In Tso et al's scheme, any one can forge a signature on an arbitrary message. Finally, we give the corresponding attack method and analyze the reason to produce such the attack, respectively. © 2011 Springer-Verlag.