An important requirement that cloud service providers must meet is the requirement of data availability. Availability assures the cloud customer that she can download her (entire) data at her convenience. Although in the use-cases for big data storage and secure processing, the cloud customer is not supposed to ever download her data, we believe that in TREDISEC this requirement should be met for all the use-cases.
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.
Proofs of Retrievability (PoR) are cryptographic proofs that enable a cloud provider to prove that the tenant can retrieve his file in its entirety. A tenant can ask the cloud provider to provide such proofs of a requested file without the need to download the file The aim of providing the PoR primitive is to provide strong assurance of storage integrity to the tenants.