用户私钥撤销是基于属性的加密(Attribute Based Encryption,ABE)方案在实际应用中所必需解决的问题.现有的支持用户私钥撤销的ABE方案通过引入用户身份的概念,以撤销用户身份的方式实现了对用户私钥的撤销,但其安全性只能达到选择性安全.本文借鉴已有方案的思想,通过将Lewko等人提出的适应性安全ABE方案与Leyou Zhang提出的适应性安全基于身份的组播加密方案相结合,利用双系统加密技术,在合数阶双线性群上实现了一个适应性安全的支持对用户私钥进行撤销的KP-ABE方案.
User's private key revocation is crucial to the practical use of ABE.The existing ABE schemes supporting user's private key revocation could revoke user's private key by introducing the concept of the user's identity and revoking user's identity.But the security of these schemes could only reach selective security.Based on the idea of the existing schemes,we construct an adaptively secure KP-ABE scheme supporting user's private key revocation on composite order bilinear groups by combining Lewko's adaptively secure ABE scheme and Leyou Zhang's adaptively secure identity-based broadcast encryption scheme.