一种可证安全无对运算的签密方案分析与改进  

Security analysis and improvement of provable security certificateless signcryption scheme

作　　者：方光伟[1,2] Fang Guangwei(School of Mathematics&Computer Science,Yichun University,Yichun Jiangxi 336000,China;School of Cyber Science&Engineering,Southeast University,Nanjing 211189,China)

机构地区：[1]宜春学院数学与计算机科学学院,江西宜春336000 [2]东南大学网络空间安全学院,南京211189

出　　处：《计算机应用研究》2020年第11期3422-3427,共6页Application Research of Computers

基　　金：国家自然科学基金资助项目(61662083)。

摘　　要：Chen等人提出了无对运算的无证书签密方案,通过加解密双方私钥和公钥相结合生成密文加密密钥,并在随机预言机模型下证明了该方案满足适应性选择密文攻击下不可区分性和适应性选择消息攻击下不可伪造性。对Chen方案进行安全分析,发现其方案在选择明文攻击下存在密钥泄露和不能抵抗恶意KGC的不可伪造性攻击问题。由此,基于椭圆曲线群上计算性Diffie-Hellman问题和离散对数问题提出了新的无证书签密方案。新方案避免了原方案的密钥泄露等安全问题。在保证安全性的前提下,新方案运行效率未降低。Chen et al.proposed a certificateless signcryption scheme without pairwise operation,which combined the private key and the public key of the encryption and decryption to generate a ciphertext encryption key.Under the random oracle model,it proved that the scheme satisfies the indistinguishability under adaptive selective ciphertext attack and the unforgeability under adaptive selection message attack.This paper analyzed the security of Chen’s scheme and found that the scheme had a key leakage under the selective plaintext attack and an unforgeable attack that could not resist the malicious KGC.Therefore,this paper developed a new certificateless signcryption scheme based on the computational Diffie-Hellman problem and the discrete logarithm problem on the elliptic curve group.The new scheme avoids the security problem such as key leakage of the original scheme.Under the premise of ensuring security,the efficiency of the new scheme has not decreased.

关 键 词：可证安全 无证书签密 随机预言机模型 机密性 椭圆曲线 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]