一种可证安全的PKI和IBC双向匿名异构签密方案的改进

异构签密可以保证异构密码系统之间数据的机密性和不可伪造性。该文分析了一个传统公钥密码(PKI)和身份密码(IBC)之间的PKI→IBC和IBC→PKI双向匿名异构签密方案的安全性，指出PKI→IBC方案和IBC→PKI方案均不能抵挡敌手攻击，敌手在获取密文前提下均可解密密文。为了增强安全性，该文提出一个改进的PKI→IBC和IBC→PKI方案，并在随机预言模型下基于计算性Diffie-Hellman困难问题和双线性Diffie-Hellman困难问题证明新方案满足机密性与不可伪造性。同时效率分析表明，所提方案具有更高的通信效率。

Improvement of a Provably Secure Mutual and Anonymous Heterogeneous Signcryption Scheme Between PKI and IBC

Heterogeneous signcryption can ensure the confidentiality and unforgeability of information data between different cryptosystems systems. Security for the traditional Public Key Infrastructure (PKI) and Identity-Based Cryptosystem (IBC) two-way and anonymous heterogeneous signcryption scheme between PKI→IBC and IBC→PKI is analyzed. It is pointed out that PKI→IBC scheme and IBC→PKI scheme can not resist adversary attacks. The ciphertext can be decrypted under the adversary obtaining the ciphertext. To enhance security, a new PKI→IBC and IBC→PKI scheme is proposed, and then confidentiality and unforgeability of the scheme in the random oracle model on the basis of the assumptions of Computational Diffie-Hellman problem and Bilinear Diffie-Hellman problem is proved. The efficiency analysis shows that the new scheme has higher communication efficiency.