前向安全的可公开验证无证书混合签密方案

Certificateless Hybrid Signcryption with Forward Security and Verifiability

签密高效地解决了在一个逻辑步骤内不能同时完成对消息签名和加密的问题.无证书混合签密方案解决了传统公钥密码体制的证书管理问题和消息长度受限问题、基于身份密码体制的密钥托管问题.本文提出一个新的无证书混合签密方案.方案利用双线性对,将无证书签密和混合加密相结合,并在随机预言机模型中利用双线性Diffie-Hellman假设证明了方案的机密性,利用计算性Diffie-Hellman假设证明了方案的不可伪造性.方案还满足可公开验证性和前向安全性,与同类方案相比具有更高的安全性;在密文长度相当的情况下,运算量更小,效率更高.

Signcryption fulfills the function of the digital signature and the public key encryption in a single logical step. While the cer- tificateless hybrid signcryption can solve the problem of the management of CA in public key encryption system and key trustee in the IBE encrypfion system, it also can handle messages of arbitrary length. We put forward a certificateless hybrid signcryption scheme which combined the certificateless signcryption with the hybrid encryption based on bilinear pairings, the scheme turn out to be secure and efficient, and it is proved to be confidential under the assumption of bilinear Diffie-Hellman problem and unforgeable under the as- sumption of compute Diffie-Hellman problem. The new scheme includes verifiability and forward security, it is more secure than the homogeneous schemes, and more efficient when the length of the ciphertext is almost the same.