基于DFA访问结构的多授权机构ABE方案设计

Design of Multi-authority Attribute-based Encryption Scheme Based on DFA Access Structure

与传统的属性基加密方案相比,基于确定性有限自动机(Deterministic Finite Automata,DFA)访问结构的属性基加密方案能够对任意长度的属性字符串进行运算,得到更加灵活的访问策略。然而,现有的基于DFA的属性基加密方案都是基于单授权机构的,系统只有一个授权机构负责整个系统的建立和密钥管理,一旦遭到攻击可能会造成密钥泄露的问题。为了解决单授权机构的密钥泄露问题,提出了一种多授权机构的基于DFA访问结构的属性基加密方案,使不同权限的授权机构管理相关密钥分发以此防止单机构遭受攻击泄露主密钥的问题。方案中,用户密钥由多个授权机构共同生成,并且和用户的身份标识绑定,能够抵抗非法用户及授权机构的共谋攻击。另外,所提方案在系统建立后仍然可以动态增加授权机构,并且授权机构的初始化公共参数与自动机的字符集无关,满足大属性集合的性质,使得方案具有良好的可扩展性。经过安全性分析,该方案在随机预言机模型下满足自适应安全。

Compared with the traditional attribute-based encryption scheme,the attribute-based encryption scheme based on DFA can operate on attribute strings of any length and obtain a more flexible access strategy.However,the existing DFA-based ABE schemes are all based on a single authority and the only one authority of the system is responsible for the establishment and key management of the entire system.Once attacked,it may cause the problem of key leakage.In order to solve the key leakage problem of single authority,a multi-authority attribute-based encryption scheme based on DFA access structure is proposed,which enables different authorities with different rights to manage related key distribution,thus preventing the single authority from being attacked and revealing the master key In the scheme,the user key is jointly generated by multiple authorities and bound with the user′s identity.The scheme can resist the collusion attack of illegal users and authority.In addition,the proposed scheme can still dynamically add the authority after the system is established,and the initialization public parameters of the authority have nothing to do with the character set of the automation,which satisfies the property of large attribute set,which makes the scheme have good scalability.After security analysis,the scheme satisfies the adaptive security under the random oracle model.