Abstract: Confidentiality and unforgeability are two main goals of secure communication. In order to solve the problem between two heterogeneous cryptographic systems, this paper proposes an efficient Traditional Public Key Cryptography（TPKC） to Identity based Public Key Cryptography（IDPKC） heterogeneous signcryption scheme. In the signcryption algorithm of this scheme, it does  not need pairing operation, in the un-signcryption algorithm, it only needs two pairing operations, efficiency has been greatly improved. Therefore, its efficiency is higher than the  existing one. In the random oracle model, based on the Computable Diffie-Hellman（CDH）hard problem, it proves that the scheme has IND-SC-CCA2 security and EUF-SC-CMA security.

Key words: heterogeneous systems, Traditional Public Key Cryptography（TPKC）, Identity based Public Key Crypto-
graphy（IDPKC）, confidentiality, unforgeability

摘要： 机密性和不可伪造性是安全通信的两个主要目标。为了解决异构密码系统之间安全通信问题，提出了一个高效从基于传统公钥密码体制到基于身份的公钥密码体制异构签密方案（TPKC→IDPKC）。该方法运行签密算法时，不需要对运算；运行解签密算法时，只需要两个对运算，与已有同类方案相比较，效率有了较大的提高；同时在随机预言模型下，基于CDH（Computable Diffie-Hellman）问题，证明该方案满足IND-SC-CCA2 安全性和EUF-SC-CMA安全性。

关键词: 异构系统, 传统公钥密码体制, 基于身份公钥密码体制, 机密性, 不可伪造性