Abstract: To reduce the loss caused by the leakage of the re-signature key, a scheme of forward-secure unidirectional threshold proxy re-signature (FSTPRS) was proposed in this paper. The re-signature key was updated in each period by one-way function while the public key remains fixed. As a result, even if the current re-signature key was exposed, the adversary could not recover the re-signature key before the current time period or forge any signatures pertaining to the past. The security of scheme was proved in the standard model. The analysis result shows that it is robust and secure against the existing forgery under the adaptive chosen message attack, under the condition of the computational Diffie-Hellman.

Key words: unidirectional threshold, proxy re-signature, forward security, provably secure, standard model

摘要： 为了降低重签名密钥被泄露所带来的损失，提出了一个前向安全的单向门限代理重签名(FSTPRS)方案，使得重签名密钥随时间段单向进化，而验证签名的公钥在整个有效时间段内保持不变，以保证即使重签名密钥被泄露，攻击者不能恢复在此之前的重签名密钥，也无法伪造在此之前的任何时间段的签名。在标准模型下证明了该方案的安全性，分析表明在计算性Diffie-Hellman假设下该方案是健壮的，并且能抵抗适应性选择消息攻击。

关键词: 单向门限, 代理重签名, 前向安全, 可证安全, 标准模型