Published Paper Details:

In cloud computing, where encryption-before outsourcing is a fundamental solution to protecting user data privacy in the distrustful cloud server environment, search over encrypted data is an extremely important enabling technique. Most of the secure search schemes have been concentrating on the single-contributor scenario, where the outsourced dataset or the secure searchable index of the dataset are encrypted and supervised by the individual owner, typically based on symmetric cryptography. In this paper, we target and concentrate on a diverse yet more challenging and defying scenario where the outsourced dataset can be contributed from multiple owners and are searchable by multiple users, that is multi- user multi-contributor case. We submit the attribute-based keyword search scheme with ef?cient user revocation (ABKS- UR) that enables scalable ?ne-grained (i.e. ?le-level) search authorization which is encouraged by attribute-based encryption (ABE). Our project related scheme will allow numerous owners to encrypt and outsource their data to the cloud server individually. Users can create their own search facilities without relying and depending on an online trusted authority. Fine- grained search authorization is also achieved by the owner-enforced access policy on the indication of each ?le. Additionally, by combining proxy re-encryption and lazy re-encryption techniques, we are capable to assign large size system update workload during user annulment to the resourceful semi-trusted cloud server. We define the security de?nition and prove the proposed ABKS-UR scheme selectively secure than chosen-keyword attack. To create con?dence of data user in the suggested secure search system, we also build and design a search result authentication and veri?cation scheme. Lastly, performance assessment shows the ef?ciency and effectiveness.