Compression Performance of Grayscale-based Image Encryption for Encryption-then-Compression Systems
This work addresses efficiency in secure image sharing on social media, but it is incremental as it builds on existing EtC systems with specific optimizations.
The paper tackles improving compression performance in Encryption-then-Compression systems for images by proposing a grayscale-based encryption method and a new JPEG quantization table, with experiments showing enhanced compression for images uploaded to and downloaded from social networks like Twitter and Facebook.
This paper considers a new grayscale-based image encryption for Encryption-then-Compression (EtC) systems with JPEG compression. Firstly, generation methods of grayscale-based images are discussed in terms of the selection of color space. In addition, a new JPEG quantization table for the grayscale-based images is proposed to provide a better compression performance. Moreover, the quality of both images uploaded to Social Network Services (SNS) and downloaded from SNS, are discussed and evaluated. In the experiments, encrypted images are compressed using various compression parameters and quantization tables, and uploaded to Twitter and Facebook. The results proved that the selection of color space and the proposed quantization table can improve the compression performances of not only uploaded images but also downloaded ones.