关键词: 数字签名, 门限签名, 无可信中心, 外部攻击, 公钥替换攻击

Abstract: This paper presents a security analysis of Gao et al’s [(t,n)] threshold signature scheme without trusted party, which can not resist outward attack and public-key attack. Besides, it also improves Gao et al’s scheme and proposes a new [(t,n)] threshold signature scheme. The improved scheme doesn’t need a trusted center, its key generation only runs an interactive protocol among all the participants, and overcomes the original scheme’s weakness. The results prove it is secure and effective.

Key words: digital signature, threshold signature, without trusted party, outward attack, public-key substitute attack