A chain-based preservation and diffusion-based internet cloud security thumbnail keeping encryption method

Abstract

This invention discloses an internet cloud security thumbnail preservation encryption method based on chain-based sum-diffusion. The main steps are as follows: Extracting the plaintext image size information and invariant features such as pixel sums for each color channel, hashing and fusing them with the master key to generate a derived key related to the image content; using the derived key to drive a chaotic system to generate a pseudo-random sequence with anti-degradation performance; employing a binary space partitioning strategy to process the three channels of the image into irregular rectangular blocks; within each independent sub-block, globally scrambling the pixel positions according to the pseudo-random sequence; finally, based on a pseudo-random traversal path, performing a chain-based sum-diffusion cyclic shift operation on each scrambled sub-block to achieve non-linear diffusion of pixel values. This invention effectively eliminates cross-channel boundary leakage that may result from regular block partitioning while ensuring the semantic usability of the encrypted image at low resolution, and significantly enhances encryption security through a dual mechanism of "scrambling-chain-diffusion".

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