关键词: 前向安全, 数字签名, 匿名性, 代理签名

Abstract: Through analyzing a forward-secure signature and a forward-secure anonymous proxy signature in the literature，the thesis points out that the two forward-secure signatures are vulnerable to be attacked and gives two improvements on the basis of them.The improved schemes with the merits of the original schemes，are able to resist the attack of the attacker and satisfy the security requirements which the original schemes don’t satisfy，much better than the original schemes.

Key words: forward-security, digital signature, anonymous, proxy signature