基于访问树的策略隐藏文件层次属性加密方案

针对具有多级层次特点的文件,提出一种高效的多机构授权的策略隐藏的属性加密方案。采用分层级的树形结构实现文件的加密,可有效抵抗合谋攻击,同时在标准假设下证明了方案的安全性。在该方案中,用户私钥由中央授权机构和多个属性授权机构共同生成,可防止私钥泄露带来的危害影响;采用分层级的树形结构加密既节省了密文存储空间又减少了加密的时间成本。该方案在文件数目较多的情况下,在加解密方面具有很高的效率。

ENCRYPTION SCHEME OF POLICY HIDDEN FILE HIERARCHY ATTRIBUTE BASED ON ACCESS TREE

Aiming at the files with multi-level characteristics,this paper proposes an efficient attribute encryption scheme with multi-agency authorization policy hiding.The scheme used hierarchical tree structure to encrypt files,which could effectively resist collusion attacks.The security of the scheme was proved under standard assumptions.The user s private key was jointly generated by the central authority and multi-agency authorization,which could prevent the harmful effects of private key disclosure.The hierarchical tree structure could save the storage space of ciphertext and reduce the time cost of encryption.In the case of large number of files,the scheme has high efficiency in encryption and decryption.