Privacy-Preserving Encryption-Domain Video Retrieval over the Cloud via Block Transformations of Key Frames

Thanks to the popularity of mobile devices and convenience of cloud computing environment, more and more people are getting use to store their captured video in the cloud; however, there's no guarantee that the stored information is not accessible to the cloud computing server, thus leading to the concern of privacy. A naïve approach to encrypt all videos before uploading them to the cloud does protect the privacy, but at the expense of seriously affecting the retrieval performance as every encrypted video should be downloaded, decrypted, and compared with the query request. We proposed to perform the video retrieval directly in the encrypted domain, i.e., in the cloud while only the desired ones will be retrieved and decrypted.