Abstract:

Source based deduplication prevents subsequent users from uploading the same file by returning a deterministic response,which greatly saves the network bandwidth and storage overhead.However,the deterministic response inevitably introduces side channel attacks.Once the subsequent uploading is not needed,an attacker can easily steal the existent privacy of the target file in cloud storage.To resist side channel attacks,various kinds of defense schemes such as adding trusted gateways,setting trigger thresholds,confusing response values,and so on are proposed.However,these methods suffer from the problems of high deployment costs,high startup costs and the difficulty in resisting random chunks generation attack and learn remaining information attack.Thus,we propose a novel secure deduplication scheme,which utilizes the random chunks attachment strategy to achieve obfuscation in response.Specifically,we first add a certain number of chunks with the unknown existent status at the end of the request to blur the existent status of the original requested ones,and then reduce the probability of returning a lower boundary value in response by scrambling strategy.Finally,the deduplication response is generated with the help of the newly designed response table.Security analysis and experimental results show that,compared with the existing works,our scheme significantly improve the security at the expense of just a little extra overhead.

Key words: cloud storage, deduplication, side channel attack, privacy security