基于Hess签名的公开可验证签密方案

Public Verifiability Signcryption Scheme Based on Hess’s Signature

利用Hess基于身份的数字签名方案,提出了一个基于身份的公开可验证加密签名方案。在BDH问题是困难的假设下,运用随机预言模型证明了该方案的安全性。方案在拥有基于身份密码体制独特优点的同时,又能保证在不访问明文的情况下,任何第三方都可以认证密文。证明了方案具有前向安全性,即使签名者的私钥泄漏,第三方也不能恢复所签密消息的明文。新方案仅需2次双线性对运算,比目前效率最高的Chen和Malone-Lee方案少1次。

Utilizing Hess＇s identity-based signature scheme, this paper proposes a public verifiability signcryption scheme. In the random oracle model, the proposed scheme is proved to be secure assuming the bilinear Diffle-Hellman problem is hard. As the authentication and recovery are separated in this scheme, anyone can identify the source of the ciphertext without the plaintext. What＇s more, the proposed scheme has forward security. Even if the secret key is compromised, the attackers can not recover the signcryption of the past time. As compared with the most efficient Chen ＆ Malone-Lee scheme to date, the proposed scheme decreases one pairing operation and only requires two pairing operations.