可追踪且可撤销的基于OBDD访问结构的CP-ABE方案

针对现有属性撤销方案中存在对恶意用户的不可追踪性、用户属性不能即时撤销的问题,提出了一种可追踪且可撤销的,基于有序二叉决策图(OBDD)访问结构的,高效、有表达力、可撤销的密文策略属性基加密(CP-ABE)方案。该方案实现了用户属性的即时撤销,也能对恶意用户进行追踪。同时,所提方案采用基于OBDD的访问结构,该类型的访问结构不仅能表示任何关于属性的布尔表达式,还能同时支持访问策略中属性的正负值。该方案将部分加/解密运算外包给代理服务器,从而降低用户的加/解密计算量。该方案基于DBDH假设,在标准模型下被证明是安全的。

Traceable and revocable CP-ABE scheme OBDD-based access structure

Aiming at the problems of untraceability to malicious users and the fact that user attributes cannot be revoked immediately in the existing attribute revocation scheme,this paper proposed a traceable and revocable ciphertex policy attribute-bose encryption(CP-ABE)scheme base on an OBDD alless striutwre,which was efficient,expressive and revocable.This scheme realized the immediate revocation of user attributes and could also be used against malicious users track.At the same time,the proposed scheme used an OBDD-based access structure.This type of access structure can not only represent any Boo-lean expressions about attributes,but also support the positive and negative values of attributes in the access strategy.This solution outsourced some encryption and decryption operations to the proxy server,thereby reducing the user’s encryption and decryption calculations.This scheme was based on the DBDH assumption and proved to be safe under the standard model.