Verifiable Ownership

To avoid client-side deduplication attacks, the new primitive called Proof of Ownership (PoW) was introduced with the aim of preventing leakage amplification in client-side deduplication. More specifically, the idea is that if an outside adversary somehow obtains a bounded amount of information about a given target user file F via out-of-band leakage, then the adversary cannot leverage this short information to obtain the whole file F by participating in client-side deduplication with the cloud storage server.
One of the main objectives of the project with respect to verifiability is the study of PoW protocols. There are indeed several open questions when it comes to this family of protocols, mostly revolving around performance and security. In addition, we plan to investigate PoW schemes that can be applied to encrypted data and/or data uploaded by participants that do not share mutual trust.

IBM's PoW

A cryptographic protocol that regulates the interactions between a prover and a verifier. The protocol is usually executed in the context of a storage outsourcing scenario, where the prover is the client and the verifier is the (storage) service provider. The correctness property of PoW schemes require that the owner of a file will succeed in convincing the verifier of this fact.