## CryptoDB

### Paper: Security Analysis of Some Proxy Signatures

Authors: Guilin Wang Feng Bao Jianying Zhou Robert H. Deng URL: http://eprint.iacr.org/2003/196 Search ePrint Search Google A proxy signature scheme allows an entity to delegate his/her signing capability to another entity in such a way that the latter can sign messages on behalf of the former. Such schemes have been suggested for use in a number of applications, particularly in distributed computing where delegation of rights is quite common. Followed by the first schemes introduced by Mambo, Usuda and Okamoto in 1996, a number of new schemes and improvements have been proposed. In this paper, we present a security analysis of four such schemes newly proposed in [15,16]. By successfully identifying several interesting forgery attacks, we show that all the four schemes are insecure. Consequently, the fully distributed proxy scheme in [11] is also insecure since it is based on the (insecure) LKK scheme [14,15]. In addition, we point out the reasons why the security proofs provided in [15] are invalid.
##### BibTeX
@misc{eprint-2003-11909,
title={Security Analysis of Some Proxy Signatures},
booktitle={IACR Eprint archive},
keywords={public-key cryptography / digital signatures, proxy signatures, security analysis.},
url={http://eprint.iacr.org/2003/196},
note={Revised version appears in the Proc. of ICISC 2003, LNCS 2971, pp. 305-319. Springer-Verlag, 2004. glwang@i2r.a-star.edu.sg 12520 received 23 Sep 2003, last revised 11 Apr 2004},
author={Guilin Wang and Feng Bao and Jianying Zhou and Robert H. Deng},
year=2003
}