@article{MFF067A95,
title = "Sub-Block-Based Compressible Perceptual Encryption Algorithm with Chroma Subsampling",
journal = "The Journal of Korean Institute of Communications and Information Sciences",
year = "2024",
issn = "1226-4717",
doi = "10.7840/kics.2024.49.8.1132",
author = "Ijaz Ahmad, Seokjoo Shin",
keywords = "perceptual encryption, jpeg, Image compression, Image encryption, chroma subsampling",
abstract = "Perceptual Encryption (PE) provides an efficient solution to the requirement of cipher images format-compatibility of photo-storage and photo-sharing applications. They deliver a desired level of security while preserving image intrinsic properties necessary to enable image processing such as image compression, in the encrypted domain. PE methods implement blockwise geometric and color transformation functions wherein the choice of block size results in a tradeoff relationship between encryption efficiency and compression savings. Nonetheless PE methods that incorporate sub-block level processing alongside block level processing can better manage this tradeoff. However, such methods have a compatibility issue with the JPEG lossy standard as the recovered images have subsampling distortions. Specifically, it cannot avoid the blur distortion resulted from the subsampling of the luminance component that is shuffled with the chroma component of the image during encryption. To address this limitation, we propose a color transformation function for the sub-block-based PE algorithms that integrates the image component shuffling step of encryption with the chroma subsampling function of compression. The simulation analyses show that the images are decoded without any visible artifacts and distortions. In addition, the proposed function reduces the datarate difference by 87% at maximum and 18% at minimum for different sub-block sizes."
}