基于格的访问控制加密技术研究

Research on the Lattice-based Access Control Encryption Technology

访问控制加密(access control encryption,ACE)是一种新颖的公钥加密概念,不仅可以保护数据的机密性,还实现了信息流向的控制.早期基于DDH(decisional Diffie-Hellman)假设的方案(DDH方案)存在密文泄露攻击且仅满足选择明文攻击(chosenplaintextattack,CPA)安全,针对此类问题,密码学家提出了访问控制加密选择密文攻击(chosenciphertextattack,CCA)安全性定义,并基于Naor-Yung的构造策略构造了CCA安全的方案.但密码学家未修补DDH方案的安全瑕疵,且其CCA方案存在效率较低、构造复杂、通信策略受限等不足.将DDH方案进行了通用化设计,并以高效的方式修补了DDH方案遭受密文攻击的瑕疵,进一步,构造了CCA安全的访问控制加密方案,具有高效、设计简单、基于标准困难性假设的特点.最后,分别基于格上困难性假设和判定性双线性Diffie-Hellman(decisional binlinear Diffie-Hellman,DBDH)假设,给出了2种CCA安全方案的实例化设计。

Access Control Encryption is a novel public-key encryption concept.It can not only protect the confidentiality of data,but also realize the control of information direction.The early scheme based on the DDH(decisional Diffie-Hellman)assumption suffers from the ciphertext leakage attack and only satisfies the chosen plaintext attack(CPA)security.For such problems,cryptologists proposed a security definition of the chosen ciphertext attack(CCA)and constructed a CCA security scheme based on Naor-Yung construction strategy.However,cryptologists have not fixed the security flaw of the DDH scheme,and their CCA scheme has shortcomings such as the low efficiency,complex construction and limited communication strategy.In this paper,the DDH scheme is designed generically,and the flaw of the DDH scheme subjected to the ciphertext leakage attack is remedied in an efficient way.Furthermore,a CCA secure access control encryption scheme is constructed,which is efficient,simple in design and based on the standard difficulty assumption.Finally,based on the lattice difficulty assumption and the decisional bilinear Diffie-Hellman(DBDH)assumption respectively,two kinds of CCA security schemes are instantiated.