A secure cloud storage system supporting privacy-preserving fuzzy deduplication

Deduplication is an important technology in the cloud storage service. For protecting user privacy, sensitive data usually have to be encrypted before outsourcing. This makes secure data deduplication a challenging task. Although convergent encryption is used to securely eliminate duplicate copies on the encrypted data, these secure deduplication techniques support only exact data deduplication. That is, there is no tolerance of differences in traditional deduplication schemes. This requirement is too strict for multimedia data including image. For images, typical modifications such as resizing and compression only change their binary presentation but maintain human visual perceptions, which should be eliminated as duplicate copies. Those perceptual similar images occupy a lot of storage space on the remote server and greatly affect the efficiency of deduplication system. In this paper, we first formalize and solve the problem of effective fuzzy image deduplication while maintaining user privacy. Our solution eliminates duplicated images based on the measurement of image similarity over encrypted data. The robustness evaluation is given and demonstrates that this fuzzy deduplication system is able to duplicate perceptual similar images, which optimizes the storage and bandwidth overhead greatly in cloud storage service.