云存储下可追踪的外包解密属性加密方案

摘要

Aiming at the problem of key tracking in cloud storage,a new attribute-based encryption scheme is proposed based on outsourcing decryption.By adding the key factor to the key,the decryption record table T of all users is generated.Data owner can monitor the decryption behavior of users at any time and provide the reference factor for detecting users maliciously spreading the decryption key.By querying the table T,data owner can quickly detect whether the key is valid for the encrypted file and obtain so user identity associated with the key.At the same time,most of the decryption operations are moved to the cloud decryption server,users only need an index operation to recover the plaintext,thus reducing the decryption work in user clients.Analysis results show that the scheme can meet the requirements of secure,efficient and traceable key management in cloud storage.%针对云存储中密钥追踪问题,基于外包解密的属性加密方案,提出一种新的属性加密方案.通过在密钥中加入密钥因子,生成所有用户的解密记录表T,数据拥有者可以随时监测用户的解密行为,为检测恶意散布解密密钥用户提供参考因子.通过查询表T,数据拥有者能快速地检测出该密钥是否为加密文件的有效密钥,并获得密钥关联的用户身份.同时解密操作大部分转移到云解密服务器中,用户只需要一次指数操作就能恢复出明文,减轻了用户端的解密工作.分析结果表明,该方案能满足云存储中密钥管理安全、高效、可追踪的要求.