针对多授权属性基加密云存储访问控制方案中的安全性和有效性问题,提出一种无中央授权中心的多授权属性加密的云存储访问控制方案.利用分布式密钥生成协议,多个授权中心联合分发用户的属性密钥;采用线性秘密共享方案,支持灵活的访问控制策略;引入代理重加密和解密外包技术,将大部分计算任务委托给云服务器执行,实现用户的即时撤销,有效降低用户的计算开销.分析结果表明,新方案在文件加密和文件解密上具有较高的性能,并且在q-BDHE假设下是自适应性安全的. Aiming at the security and validity of multi-authorization-based cloud storage access control scheme, this paper proposes a cloud storage access control scheme without multi-authorization attribute-based encryption of central authorization center.Using distributed key generation protocol, multiple authorizations The center jointly distributes the user’s attribute key; adopts the linear secret sharing scheme to support the flexible access control strategy; introduces the agent re-encryption and decryption outsourcing technology, delegates most of the computing tasks to the cloud server for implementation, realizes instant withdrawal of users and effectively reduces User’s computational cost.The analysis results show that the new scheme has high performance in file encryption and file decryption and is adaptive and secure under the q-BDHE assumption.