Abstract: The security problem of the data stored in the cloud is a challenge for cloud computing. Encryption is the main method to solve the problem of data storage security in cloud computing. The confidentiality issue of the encryption is the key management. The attribute-based encryption and re-encryption scheme in cloud computing was proposed. It combined attribute-based encryption and re-encryption technology. The cloud server could re-encrypt for different users, and re-encrypt for a group of users at a time. Thereby the scheme reduced the number of re-encryption keys. The data owner could generate and send the keys of re-encryption for a group of users and the data requester could use the key corresponding to the attribute set to decrypt the data of several data owners, which reduced the amount of keys’ transmission. The scheme reduced the difficulty of key management and improved the efficiency of the scheme. In the end, the security and efficiency of the scheme were discussed.

Key words: cloud computing, cloud security, attribute-based encryption, re-encryption, key management

摘要： 在云计算环境中如何安全地存储数据是云计算面临的挑战之一。加密是解决云计算中数据存储安全问题最主要的方法，而加密的一个保密性问题是密钥管理。提出了云环境下的基于属性和重加密的密钥管理方案。云服务提供商对不同用户进行重加密时，可以一次为一组用户重加密，从而减少了重加密的个数。数据拥有者可以对组用户生成和发送重加密密钥，而数据请求者可以使用属性集对应的一个密钥解密多个数据拥有者的数据，从而能减少两者的密钥发送量，降低密钥管理的难度，提高方案的效率。最后，对方案的安全性和性能进行了分析

关键词: 云计算, 云安全, 基于属性的加密, 重加密, 密钥管理