Abstract: Heterogeneous system signcryption schemes mostly use the public key encryption technology, which can not encrypt any long messages, and it is unsuitable for actual application situation. Therefore, this paper proposes a hybrid signcryption scheme based on heterogeneous cryptosystem. The heterogeneous signcryption scheme is from the identity-based cryptography system to the certificateless cryptography system. Simultaneously, the scheme not only satisfies that the private key generator and the key generation center can generate their own private master key respectively, but also satisfies confidentiality and unforgeability on the basis of the assumption of bilinear Diffie-Hellman difficult problems and Diffie-Hellman difficult problem, in the random oracle model.

Key words: heterogeneous systems, hybrid signcryption, Identity-Based Cryptography（IBC）, Certificateless Cryptography（CLC）, random orade model

摘要： 针对异构密码系统的签密算法大多采用的是公钥加密技术，不具有可加密任意长消息的特点，不符合现实的应用环境，而混合签密技术则可解决这一不足。提出了一个基于异构密码系统的混合签密方案。该方案是由基于身份的密码（Identity Based Cryptography，IBC）体制到无证书密码（Certificateless Cryptography，CLC）体制的异构签密方案。不但能使私钥生成器（Private Key Generator，PKG）和密钥生成中心（Key Generating Center，KGC）分别在IBC密码体制和CLC密码体制中产生自己的系统主密钥，同时，在随机预言模型下，方案在计算性Diffie-Hellman和双线性Diffie-Hellman困难问题下具有不可伪造性和不可区分性。

关键词: 异构密码系统, 混合签密, 基于身份的密码学, 无证书密码学, 随机预言模型