基于离线密钥分发的加密数据重复删除方法

重复数据删除技术受到工业界和学术界的广泛关注.研究者致力于将云服务器中的冗余数据安全的删除，明文数据的重复删除方法较为简单.而用户为了保护隐私，会使用各自的密钥将数据加密后上传至云服务器，形成不同的加密数据.在保证安全性的前提下，加密数据的重复删除较难实现.目前已有的方案较多依赖在线的可信第三方.提出一种基于离线密钥分发的加密数据重复删除方案，通过构造双线性映射，在不泄露数据隐私的前提下，验证加密数据是否源自同一明文.利用广播加密技术实现加密密钥的安全存储与传递.任意数据的初始上传者能够借助云服务器，以离线方式验证后继上传者的合法性并传递数据加密密钥.无需可信第三方在线参与，实现云服务器对加密数据的重复删除.分析并证明了方案的安全性.仿真实验验证了方案的可行性与高效性.

Secure Encrypted Data Deduplication Method Based on Offline Key Distribution

Secure data deduplication has received great attention from both academic and industrial societies. It is highly motivated for cloud service providers to delete duplicated data from their storage. Plaintext data deduplication is a simple problem, but users tend to encrypt their data with their own keys before uploading them to the cloud, which makes it difficult to perform cross user deduplication. Most current solutions to the problem rely on trusted third parties. An encrypted data deduplication scheme is presented based on an offline key distributionprotocol. A bilinear mapping is constructed to verify whether different encrypted data originate from the same plaintext. Secure key storage and key delivery is achieved by using the broadcast encryption technique. An original uploading user of some data can validate successive uploading users via the cloud service provider, and the data encryption key can be distributed in an offline manner. The cloud service provider can accomplish encrypted data deduplication with no online interaction withany trusted third party. The security of the proposed scheme is analyzed and proven. Simulation experiments show that the scheme is efficient and applicable.