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Image compression and encryption method based on wavelet transform and SHA-1 (secure has algorithm-1)

A technology of wavelet transform and image compression, applied in image communication, digital video signal modification, selective content distribution, etc., to achieve large key space, improve image storage and transmission efficiency, and resist exhaustive attacks

Inactive Publication Date: 2015-07-15
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of SHA-1 can increase the sensitivity of the algorithm to plaintext, and the DCT-based image compression encryption algorithm has a good concealment effect, but because the method uses block-based DCT transformation, there will be obvious block effects when the compression ratio is high

Method used

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  • Image compression and encryption method based on wavelet transform and SHA-1 (secure has algorithm-1)
  • Image compression and encryption method based on wavelet transform and SHA-1 (secure has algorithm-1)
  • Image compression and encryption method based on wavelet transform and SHA-1 (secure has algorithm-1)

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specific Embodiment

[0064] Utilize general-purpose microcomputers, such as Intel Pentium 4 series microcomputers. Develop a compression encryption system in the MATLAB2009a programming environment. The program running platform is intel P43.0G CPU+2GB memory.

[0065] In the first step, set the initial key Key as [x 0H ,p 0H 、x 0L ,p 0L 、c 0 ], set the parameters to [0.405000869748940, 0.630979255024048, 0.421150774180423, 0.594355626412632, 3853080679] (subscript H means high frequency, L means low frequency). Calculate the sum of image pixel values, and its modulo 256 result is recorded as a=135. At the same time, 4 layers of lifting wavelet transform are performed on the original image, and the low sub-band LL 4 The coefficients are converted into a sequence L by column scanning, L and a form a sequence W, and the rest of the wavelet coefficients are divided into three parts: HL, LH, and HH according to the horizontal, vertical, and diagonal directions, and each part still maintains the ...

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Abstract

The invention relates to an image compression and encryption method based on wavelet transform and SHA-1 (secure has algorithm-1) and aims to encrypt in image compression process. According to the algorithm, an image is subjected to four-layer wavelet decomposition first, and coefficients are divided into a low-frequency portion and a high-frequency portion after decomposition. Low-frequency coefficients, initial keys and original image pixels are used to generate 160-bit hashed values by SHA-1, and the hashed values generate subkey scrambled high-frequency coefficients. The scrambled high-frequency coefficients are subjected to SPIHT (set partitioning in hierarchical trees) encoding, and the initial keys disturbed by the hashed values are used to partially encrypt encoded data streams. Part of the encrypted high-frequency coefficients and the initial keys are used as input messages for SHA-1. The subkey scrambled low-frequency coefficients are generated by the hashed values, the scrambled low-frequency coefficients are subjected to Huffman encoding, and then the initial keys are disturbed by the hashed values to encrypt the encoded data streams, so that low-frequency coefficients are encrypted. Input information is sensitized by SHA-1, the low-frequency portion and the high-frequency portion are mutually encrypted, and accordingly image information safety is guaranteed.

Description

technical field [0001] The invention belongs to image compression and encryption methods, in particular to an image compression and encryption method based on wavelet transform and SHA-1, which is a compression and encryption algorithm aimed at the security problem of image layered number set division encoding, and is suitable for high compression occasions . Background technique [0002] With the richer multimedia content and the increasing demand for secure transmission in public networks, digital image compression and encryption technology has attracted increasing attention. In the field of image compression, people have broken through the traditional source coding theory and made full use of the characteristics of human vision and image source to continuously improve image compression performance. However, while these algorithms achieve better compression effects, they ignore the security of image information. In the field of image encryption, chaotic systems are espec...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04N19/63H04N19/88H04N21/2343H04N21/2347
Inventor 张绍武李园园陈韬
Owner NORTHWESTERN POLYTECHNICAL UNIV
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