Anonymous deduplication of encrypted data with proof of ownership in cloud storage

Cloud computing is viewed as the next generation architecture of IT companies. As promising as it is, cloud computing also brings forth many new security issues when users outsource sensitive data to cloud servers. To keep sensitive users´ data confidential against untrusted servers, existing solutions usually apply cryptographic methods. With data encryption, the same file will become different from each other, thus deduplication which is widely adopted by cloud storage service providers meets some challenges. Current method to solve the problem is to make use of some information computed from the shared file to achieve deduplication of encrypted data, say convergent encryption. But this piece of information which is computable from the file via a deterministic public algorithm is not really meant to be secret. To this end, we propose a scheme to address the deduplication of encrypted data efficiently and securely with the help of ensuring the ownership of the shared file, encrypting data using keys at user´s will and realizing the anonymous store through the digital credential. We achieve this aims through proof of ownership (POW), proxy re-encryption (PRE) and digital credential.