大属性可公开追踪的密文策略属性基加密方案

Publicly Traceable Accountable Ciphertext Policy Attribute Based Encryption Scheme Supporting Large Universe

密文策略属性基加密可以灵活实现"一对多"加密,尤其是大属性的属性基加密,可以支持任意的属性全集,因此在云计算、物联网、大数据等领域有广泛应用前景。然而,密文策略属性基加密中同一个解密私钥可以对应多个不同的用户,于是恶意用户敢于共享其(部分)私钥以获取非法利益。针对用户恶意共享解密私钥的问题,为实现公开追踪并验证泄露私钥拥有者身份的目的,文中提出一个支持大属性的可公开追踪的密文策略属性基加密方案,该方案可以支持任意单调的访问结构。并且,除了固定长度的系统公开参数外,不花费额外的存储代价就可以对泄露密钥的用户身份进行公开验证。

Ciphertext policy attribute-based encryption can achieve one-to-many encryption flexibly.Especially,the large universe attribute-based encryption can support unbounded attribute universe,and has extensive applications in cloud computing,big data,etc.However,owing to the fact that a private decryption key may correspond to different users,thus malicious users dare to share their decryption privileges to others for profits.To solve this problem and publicly verify the identity of a leaked secret key,this paper proposes an accountable attribute based encryption scheme that supports large universe.The proposed scheme can support LSSS realizable access structures.In addition to the fixed-length system public parameters,the identity of the user who leaks the encryption key can be publicly verified without considering the constant storage cost.