On the Proxy-Protected Property of Chen et al.'s Proxy Multisignature Schemes

Recently, Chen, Chung, and Huang proposed a traceable proxy multisignature scheme based on the elliptic curve cryptosystem. However, this paper shows that the original signers can produce a valid signature as the proxy signer does in the proxy protected scheme. Therefore, Chen et al.’s proxy-protected scheme cannot protect the proxy signer from being forged by the original signers. We further find that the early work of Chen et al. in 2003 suffers the same attack. To overcome this problem, an improved scheme will be presented. Key words: proxy signature, proxy multisignature, proxy-protected, elliptic curve, digital signature.

• Type: Journal
• Year: 2007
• Where: INFORMATICALT
• Authors: Pei-Hui Huang, Hsiang-An Wen, Chih-Hung Wang, Tzonelih Hwang
• Keywords: Elliptic Curve, INFORMATICALT 2007, Original Signers, Proxy Signer