Self-recovery image encryption and decryption method combining zero watermarks and block classification fusion

Abstract

The invention provides a self-recovery image encryption and decryption method combining zero watermarks and block classification fusion. During encryption, first, small blocks are divided into four types according to a frequency domain alternation coefficient of the small blocks in an image to be encrypted, and corresponding alternating current and direct current coefficients are reserved to serve as a restoration reference matrix; second, main information of the small blocks which are scrambled in position and auxiliary information of an original position reference matrix are fused, and authentication information of the fused small blocks is acquired according to an encoding matrix; third, direct current components and the block types of the scrambled small blocks before fusion and the authentication information of the fused small blocks are used as the zero watermarks stored in a third public trust party; and last, the image is reconstructed from the fused small blocks, and global position scrambling is performed to generate an encrypted image. During recovery, first, the fused small blocks are reconstructed, the main information and auxiliary information authentication relation and zero watermark recovery main information are utilized, and a decrypted image is reconstructed. Compared with existing methods, the method can be used for effectively encrypting the image and performing a certain recovery against a channel attack, thereby having higher application value.

Description

technical field [0001] The invention belongs to the cross field of image security and image signal processing, relates to an image encryption and decryption method, in particular to a self-restoring image encryption and decryption method combined with zero watermark and block classification fusion. Background technique [0002] For image encryption, several image encryption methods have been proposed: [0003] ① An image encryption method that confuses and encrypts images by changing pixel values, for example: Peng Zaiping, 2014 (Peng Zaiping, Wang Chunhua, Lin Yuan, etc. A new type of four-dimensional multi-wing hyperchaotic attractor and its application in image encryption Research in [J]. Acta Physica Sinica, 2014, 63(24): 240506-1–240506-10) and Zhu Congxu et al., 2012 (Zhu Congxu, Sun Kehui. Cryptanalysis and improvement of a class of hyperchaotic image encryption algorithms[J ]. Acta Physica Sinica, 2012, 61(12):12503-1-12503-12) XOR-encrypts image pixel values ​​by g...

AI Technical Summary

Problems solved by technology

[0008] Although a large number of image encryption methods have been proposed, the existing image encryption methods usually focus on how to effectively and safely construct encryption strategies, while the attention to the anti-attack ability of encrypted images is relatively limited. Although some image encryption methods have certain anti-attack Ability, but the ability to resist attacks is very limited and the image encryption methods given above do not have the ability to repair after the attack

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