标准模型下可证明安全的无证书广义签密

摘要

Liu等在2010年提出了一种在标准模型下可证明安全的无证书签密算法(简称LHZ算法),但后续的研究成果显示LHZ算法实际上是不安全的.为了克服LHZ算法的不足,首先改进LHZ签密算法,然后以此为基本的签密算法提出一种新的无证书广义签密算法.同时给出了抵抗有预谋的KGC被动攻击(malicious-butpassive KGC attack)的无证书广义签密算法的安全性模型,并在标准模型下证明了该算法在判定性双线性Diffie-Hellman困难问题和计算性Diffie-Hellman困难问题假设下是安全的.此外,数值实验结果表明所提方案是有效的.%In 2010,Liu,et al.proposed a certificateless signcryption scheme in the standard model,but many analyses revealed that Liu's scheme was insecure in fact.To overcome the disadvantages,the scheme was improved and a certificateless generalized signcryption scheme was constructed.In addition,a formal security model for the proposed scheme against the malicious-but-passive KGC attacks was introduced.Furthermore,the proposed scheme was proven to be secure under the decisional bilinear Diffie-Hellman and the computational Diffie-Hellman intractability assumptions in the standard model.Numerical results illustrate that the proposed algorithm is efficient.