E-TPE: E fficient T humbnail- P reserving E ncryption for Privacy Protection in Visual Sensor Networks

Abstract

When visual sensor networks (VSNs) enter daily life in society, they not only bring great convenience but also cause people to worry about privacy. Traditional image encryption often displays the effect of the enter snowflake in encrypted images playing a part in privacy protection, but the usability of directly browsing images taken by nodes in VSNs is sacrificed. Recently, thumbnail-preserving encryption (TPE) has been proposed to balance image usability and privacy. However, the Markov chain’s limited connectivity and high time cost, which result in low efficiency, may preclude its application in VSNs. Motivated by this, we propose a novel TPE scheme to protect the image collected in VSNs privacy efficiently. We first deeply study the bijective relationship between the three-pixel group and its rank, and then propose a new number method for both, based on which we design the efficient rank mapping. Subsequently, an efficient thumbnail-preserving image encryption via three-pixel rank mapping (E-TPE) is designed, achieving NR security and enhancing the Markov chain’s connectivity. The experiments demonstrate the scheme’s efficiency, that is, it is the currently quickest ideal-TPE scheme with NR security, and that a good balance is achieved between usability and privacy.