Just process me, without knowing me: a secure encrypted domain processing based on Shamir secret sharing and POB number system

Abstract

High end computational and storage resources provided by the cloud based paradigm are attracting the global infrastructure. However, the wide attacking surface of the public cloud may pose threat to security if outsourcing of the multimedia content is done without obscuring. Employing the traditional encryption schemes may serve as a feasible solution. However, processing in the encrypted domain to fetch the same services as plaintext domain may not be possible due to limitations of the encryption schemes. In this article, a secured scheme based on Shamir's secret sharing and permutation ordered binary (POB) number system for processing of image in encrypted domain itself over the cloud severs has been proposed. Obfuscated shares are obtained by distributing the image information into multiple shares that can be sent and processed in frequency domain over the cloud servers. The performance of various image operations such as denoising, dehazing, edge sharpening, unsharp masking, contrast enhancement, etc has been validated on these encrypted shares in the frequency domain along with the comparative results in the plaintext domain. The processed image can be obtained from these processed shares only by the authentic entity possessing the secret keys.