Color JPEG image format-compliant encryption and decryption method

Abstract

The invention discloses a Color JPEG image format-compliant encryption and decryption method, comprising the following steps of: S1: determining the scale LT of a block T to be extracted; S2: selecting a ROI block from the compressed data segment of the original JPEG image, re-selecting the ROI block or supplementing a random block to the ROI block according to the relationship between the ROI block and the T size to make the ROI block equal to the T scale; S3: performing RC4 encryption on the block obtained in S2 to form an encrypted block; S4: scrambling and rearranging the remaining blocksin the compressed data segment of the original JPEG image; S5: reorganizing the block generated in S3 and the block scrambled and rearranged in S4 into a format-compliant encrypted JPEG image; S6: performing image restoration or image decryption. The compliant encrypted image block information according to the Color JPEG image format-compliant encryption and decryption method also changes the structure of the original image to make the encrypted image difficult to recognize. The method improves the validity and reliability of the algorithm, provides protection for the ROI, adapts to differentapplication scenarios, and retains the capability of performing certain detection and processing on the encrypted JPEG image, and can provide assistance for applications such as a cloud monitoring system and a cloud storage system.

Description

technical field [0001] The invention relates to the field of multimedia information security, in particular to a format-compatible encryption method for color JPEG images. Background technique [0002] In recent years, with the development of multimedia technology, image processing technology has increasingly appeared in people's daily life. At the same time, people pay more and more attention to the development of privacy protection technology for image content. In addition, people pay more and more attention to the speed of picture transmission, especially when a large number of pictures need to be transmitted. Due to the limited bandwidth, if the original picture is not processed to some extent, the transmission will consume a lot of bandwidth and time. [0003] Therefore, JPEG, as an image format that can compress images to reduce their size, save bandwidth and increase transmission speed while maintaining high quality of images, has been popular in various industries in...

AI Technical Summary

Problems solved by technology

However, for JPEG, the existing encryption methods mainly encrypt the airspace and time domain related parameters in the JPEG code stream. From the perspective of security, such algorithms have the risk of privacy leakage.

In particular, these encryption algorithms do not change the structure of the image itself, and the structure of the image itself is accompanied by a large amount of side information. If it is not encrypted and modified, it is likely to lead to privacy leaks, which makes the security not obtained. adequate protection

[0004] Although some algorithms recently encrypt the parameters of the frequency domain and also change the structure of the image, compared with most other JPEG encryption algorithms, the security has been significantly improved, but on the one hand, they often only One encryption method is adopted instead of multiple encryption systems; on the other hand, encrypted JPEG images are often used in scenarios such as cloud storage systems, such as embedding and retrieving watermarks on encrypted JPEG images on cloud servers, or image processing Retrieval, etc. These need to retain a certain processing power for encrypted JPEG images, and those algorithms often cannot do this well

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