Abstract: Combining mediated encryption with Certificateless Public Key Encryption（CL-PKE）, a new Variant Mediated Identity-Based Encryption (V-MIBE) scheme based on computational bilinear Diffie-Hellman assumption was presented. New scheme not only solved the problem of key escrow by the idea of CL-PKE but also provided fast key revocation with mediator. New scheme can resist the attack of replacing user's public key. Compared with the existing identity-based encryption scheme, the security of new scheme improves remarkably.

Key words: key escrow, key revocation, mediator, Variant Mediated Identity-Based Encryption (V-MIBE), Security Mediator (SEM)

摘要： 将基于仲裁的身份加密与无证书加密相结合，设计了一个基于仲裁的身份加密(V-MIBE)方案。新方案利用椭圆曲线上的双线性映射构造，通过无证书加密思想解决密钥托管的问题，通过引入仲裁机构解决密钥撤销的问题，新方案能够抵抗替换用户公钥的攻击。与现有的基于身份的加密方案相比，新方案的安全性能显著提高。

关键词: 密钥托管, 密钥撤销, 仲裁者, 基于仲裁的身份加密, 仲裁实体