Thumbnail Encryption Learning Summary

1. Overview of thumbnail encryption

After fully encrypting to a noise image, the file size of the ciphertext image will expand, and more resources will be consumed for transmission and storage. The availability of fully encrypted noisy images is based on decrypting the ciphertext, which is computationally expensive. The fine visual information in the original image is erased to protect privacy, while the rough visual information is preserved to keep usable, legitimate users with prior knowledge can combine the prior knowledge and the rough visual content in the ciphertext image to make proper reasoning Thereby identifying the image, which is not possible for illegitimate third parties without prior knowledge.

2. Application scenarios

1. Lightweight and safe storage of image big data.
2. Balance usability and security.
3. The owner can control the balance between privacy security and usability by adjusting the size of the thumbnail block.
4. Image Copyright Trade Online. Thumbnail encryption can be regarded as a low-resolution version of the original image (controlled by the image owner), and the TPE version of the image can be displayed on the trading platform for buyers to make a rough perception to determine whether to purchase. When the buyer pays, That is to provide the original image for buyers to decrypt.

3. Overall framework

Encryption process:
pixel scrambling in a block;
recursive block encryption: block scrambling in a block + pixel scrambling in a block; the
encrypted pixel image uses JPEG compression to generate a JPEG image;

encryption effect The encryption
effect diagram under different block sizes:

4. Literature on Thumbnail Encryption

1. Wright C V, Feng W C and Liu F. 2015. Thumbnail-preserving encryption for JPEG/ / Proceedings of the 3rd ACM Workshop on Information Hiding and Multimedia Security. Portland, USA: ACM:141-146.
2. Tajik K, Gunasekaran A, Dutta R, Ellis B, Bobba R B, Rosulek M, Wright C V and Feng W C. 2019. Balancing image privacy and usability with thumbnail-preserving encryption/ / Proceedings of 2019 Network and Distributed System Security Symposium. San Diego, USA: The Internet Society.
3. Zhao R Y, Zhang Y S, Xiao X L, Ye X and Lan R S. 2021. TPE2: three-pixel exact thumbnail-preserving image encryption. Signal Processing, 183: #108019.
4. Zhang Y M, Zhao R Y, Zhang Y S, Lan R S and Chai X L. 2022b. High-efficiency and visual-usability image encryption based on thumbnail preserving and chaotic system. Journal of King Saud University-Computer and Information Sciences, 34 (6 ): 2993-3010.
5. Marohn B, Wright C V, Feng W C, Rosulek M and Bobba R B. 2017. Approximate thumbnail preserving encryption/ / Proceedings of 2017 on Multimedia Privacy and Security. Dallas, USA: ACM: 33-43.
6. Zhang Y S, Zhao R Y, Xiao X L, Lan R S, Liu Z and Zhang X P. 2022a. HF-TPE: high-fidelity thumbnail-preserving encryption. IEEE Transactions on Circuits and Systems for Video Technology, 32(3): 947-961.