Four-pixel sum-preserving encryption using the chaotic map for high thumbnail-preserving image security.

Chia-Hung Kao, Guan-Zhen Chen, Yi-You Hou, Teh-Lu Liao

Abstract read

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Article in Scientific reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 · Who and what money

Authors and funding

4 authors.

Chia-Hung KaoDepartment of Engineering Science, National Cheng Kung University, Tainan, 701, Taiwan. n98134015@gs.ncku.edu.tw.

Guan-Zhen ChenDepartment of Aviation Communication and Electronics Air Force Institute of Technology, Kaohsiung, 820, Taiwan.

Yi-You HouDepartment of Intelligent Commerce, National Kaohsiung University of Science and Technology, Kaohsiung, 824, Taiwan. yyhou@nkust.edu.tw.

Teh-Lu LiaoDepartment of Engineering Science, National Cheng Kung University, Tainan, 701, Taiwan. tlliao@mail.ncku.edu.tw.

Funding

National Science and Technology Council NSTC 114-2221-E-006-171

6 · The paper itself

Abstract

The utilization of cloud-based photo-sharing services has been observed to result in the exposure of thumbnails, thereby engendering a privacy risk. Thumbnail-preserving encryption (TPE) is a method of mitigating this issue by encrypting images while maintaining the usability of thumbnails. Existing sum-preserving encryption (SPE) typically operates on 3-pixel groups, which are not aligned with power-of-two block sizes and can leave residual plaintext when tiling. The proposed mapping is a four-pixel SPE (4px-SPE) mapping, which is a piecewise bijection on 8-bit pixel quadruples that exactly preserves the four-pixel sum and is perfectly invertible. The scheme is integrated into a permutation-substitution TPE framework. It uses a 256-bit master key with deterministic, hash-based key derivation to reproduce per-image and per-block schedules, and to derive per-block keystreams and permutations without relying on plaintext-derived key material. A mathematical proof and exhaustive verification of all 256

Indexed as

Chaotic mapFour-pixel encryptionSecurity analysisSum-preserving encryption (SPE)Thumbnail-preserving encryption (TPE)

Identifiers

PMID42420326

DOI10.1038/s41598-026-47090-9

PMCPMC13346532

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LicenceCC BY-NC-ND

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.