【摘要】 针对当前属性基加密系统中用户与中心滥用密钥以及用户解密权限的撤销问题,提出一种支持追责和用户撤销的属性基加密方案.该方案使用"不动点"作为密钥拥有者的标识符,实现了对恶意用户的身份追踪;通过用户与中心交互生成解密密钥,解决了半信任中心滥用密钥的问题;利用完全子集方案和自更新加密方案实现了用户的即时撤销,并达到了前向/后向安全性;同时使用Paillier加密体制,避免了追踪过程中的存储代价.该方案无需在系统建立阶段预先确定属性个数,且在标准模型下被证明是选择明文安全的.更多还原

【Abstract】 Aiming at the problems of the current attribute-based encryption system,such as the issues of users and center abused keys and decryption rights of user revocation,we proposed an attributebased encryption scheme that supported accountability and user revocation.The scheme used a"fixed point"as the identifier of the key owner to realize the identity tracing of malicious users.The decryption key was generated by interaction between user and center to solve the problem that semi-trusted center abused keys.By using complete subset scheme and self-update encryption scheme,the proposed system could achieve immediate revocation and forward/backward security.Furthermore,we used a Paillier encryption system to avoid storage cost in the tracing process.The scheme didn’t need to predetermine the number of attributes at stage of system setup,and was proved to be chosen-plaintext security in the standard model.更多还原