Recovering tampered regions in encrypted video using POB number system

Abstract Explosive growth in multimedia contents and wide spectrum of facilities provided by the cloud paradigm is attracting the global infrastructure towards it. However, the security and privacy issues of the outsourced content while availing these cloud based services is one of the major concerns. To secure the content, the traditional way is to render the data encrypted prior to outsourcing. However, just encrypting the data does not ensure that the content is intact as there may be attack attempts on the encrypted content. Hence, in this paper, an approach has been proposed to ensure the integrity of the content in the encrypted domain. If any breaches are attempted at the third party cloud service providers which alters the content in the encrypted form, the proposed scheme is able to first detect these tampered regions very accurately at the pixel level and thereafter, is capable of recovering the tampered content in the encrypted domain itself. Further, the overheads of bandwidth transmission are minimized here as the original information, spatial tampering bits, temporal tampering bits as well as the recovery information are compacted very efficiently exploiting the properties of the Permutation Ordered Binary (POB) number system. The scheme has been specifically tested with video contents as they contribute a major portion of the ever increasing multimedia repository. The efficacy of the scheme has been validated by testing against various attack scenarios and the scheme has been found to be performing satisfactorily well.