Cryptanalysis of Two Nominative Proxy Signature Schemes
Yu Yong①; Xu Chun-xiang①; Zhou Min②; Li Fa-gen①③
①School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China;②College of Information, South China Agricultural University, Guangzhou 510642, China; ③Key Lab of Computer Networks and Information Security of Ministry of Education, Xidian University, Xi’an 710071, China
Abstract：Analyses of two nominative proxy signature schemes proposed by Seo et al.(2003) and Huang et al. (2004) are given in this paper. The results show that neither the scheme has the property of strong unforgeability. A forgery attack on the two schemes is given, respectively. Using the forgery attack, a dishonest original signer can forge a proxy signing key on behalf of the designated proxy signer by assigning some parameters and produce valid nominative proxy signatures, which does harm to the benefits of the proxy signers.
2009, Vol. 31 
