Abstract: Forward security signature scheme satisfies forward security. However, the scheme is not secure if signature’s secret key is revealed. For this reason, this paper proposes a new strong forward security proxy signature scheme combining strong forward security and proxy signature, which introduces strong forward concept and overcomes limitation of the previous scheme.

Key words: forward security, afterward security, strong forward security, proxy signature

摘要： 分析一种基于ElGamal的前向安全签名方案。该方案满足前向安全性，但在签名者私钥泄漏后，签名是不安全的，即不满足后向安全性，有一定的局限性。该文引入强前向安全的思想，克服了该方案的局限性，并将改进后的强前向安全签名与代理签名相结合，提出一种新的满足强前向安全定义的强前向安全代理签名方案。

关键词: 前向安全, 后向安全, 强前向安全, 代理签名

CLC Number: 

• TP309