Privacy preserving image scaling using 2D bicubic interpolation over the cloud

This paper presents an efficient scheme for privacy preserving image scaling over the cloud. The proposed scheme advances the emerging trend of privacy preserving cloud computing and supports desired operations required for image scaling in the encrypted domain. We use scaling and randomization followed by modulo operation for generation of image shares and employ 2D bicubic interpolation for scaling user images in the encrypted domain. The previous scheme used bilinear interpolation utilizing four neighboring pixel intensity values to approximate intermediate ones while scaling the image. On the contrary, we use sixteen neighboring pixel intensity values utilizing bicubic interpolation by leveraging considerable efforts to support the processing of user images over cloud servers. The proposed scheme is validated through various experiments followed by a comparison with the existing scheme. Additionally, security analysis demonstrates the robustness of the proposed scheme under various attack scenarios.