Selective Encryption Method for Digital Image Oriented to Mobile Phone Service

Abstract

A mobile-service-oriented digital image selective encryption method includes the steps of image wavelet sub-band selection, chaotic sequence initial value determination, image encryption and encryption quality evaluation. An important fraction wavelet low-frequency sub-band is selected by computing an important value of each scale fraction wavelet low-frequency sub-band of an original image and serves as an image low-frequency sub-band to be encrypted, but not all the image sub-bands are encrypted; A set of four parameters serves as a key of image encryption, and a chaotic encryption sequence initial value of the selected fraction wavelet low-frequency sub-band to be encrypted is determined by completely depending on the selected important low-frequency sub-band; Chebyshev mapping, rather than Logistic mapping, is adopted to encrypt the selected low-frequency sub-band; and the sum of the reciprocal of the peak signal-to-noise ratio with the image edge difference ratio serves as quantitative evaluation of image encryption quality, and the quality of image encryption is not judged only by visual inspection.

Description

technical field [0001] The invention relates to a digital image selection and encryption method for mobile phone services, in particular to the selection of image wavelet subbands, the determination of initial values ​​of chaotic sequences, image encryption and encryption quality evaluation methods. Background technique [0002] Today, with the popularity of wireless Internet, mobile phone service has become the fastest growing and most promising field in the entire information industry, which has an important impact on urban construction and national economic development. Mobile phone service is an important part of urban construction, and images are an important form of information resources. Images not only involve personal privacy, business secrets, corporate survival and development, and military secrets, but also, due to the openness of the mobile phone environment, there are higher requirements for the security of digital images, so the security of image resources in ...

AI Technical Summary

Problems solved by technology

Images not only involve personal privacy, business secrets, corporate survival and development, and military secrets, but also, due to the openness of the mobile phone environment, there are higher requirements for the security of digital images, so the security of image resources in mobile phone services is more important. challenge

In addition, the mobile phone itself takes the embedded operating environment as the technical core, pursues its own mobility, convenience, low power consumption and low cost, and its processor computing power, memory capacity and equipment energy consumption are greatly limited. The security implementation of digital images in mobile phone services faces many technical bottlenecks:

[0003] (1) The data volume of digital images is generally relatively large, directly using the classical cryptographic mechanism will consume too much processing time, and the calculation efficiency is not only too low, but also unbearable

[0004] (2) The direct use of classical cryptographic mechanisms for digital images involves mutual conversion between binary bit strings and high-dimensional matrices, which reduces the efficiency of image encryption

[0005] (3) Digital images belong to discrete sampling coding rather than continuous coding, there is a strong correlation between adjacent pixels, and there is a lot of visual redundancy

Its shortcoming is that this method of selecting the pixel set of interest is computationally expensive and cannot be directly used in mobile phone services

Images