Multi-image encryption method based on fractional mellin transform

Abstract

The invention provides a multi-image encryption method based on fractional mellin transform. The method includes the steps of compressing multiple images according to a frequency spectrum cutting and splicing method, then, dividing an image obtained through compression into a plurality of sub-images according to an annular domain, conducting fractional mellin transform on all the sub-images, encrypting a fractional mellin transform outcome into a cryptograph image through magnitude and phase encoding, taking transform degrees of fractional mellin transform as secret keys, and taking a center coordinate for coordinate transform, an inner radius of the annular domain for implementation of transform and an outer radius of the annular domain for implementation of transform as secondary secret keys. According to the multi-image encryption method, the multiple images are compressed through the real-value characteristics of fractional cosine transform, and therefore overweight transmission loads are avoided, and the requirement for instantaneity of image data transmission is met. Fractional mellin transform is then conducted on the image obtained through compression, the fractional order characteristic, the nonlinear characteristic and the like of the fractional cosine transform are fully utilized, and the multi-image encryption method has quite high robustness in terms of clipping prevention and noise prevention. The nonlinear operation is introduced into an encryption system while multi-image encryption transmission can be ensured, and safety of the encryption system is enhanced.

Description

technical field [0001] The patent of the present invention belongs to the field of information security technology, and in particular relates to multi-image compression and encryption technology. Background technique [0002] With the rapid development of network multimedia technology, communication technology and transmission technology, hidden dangers of network information security inevitably arise. Information security has become a problem that people cannot ignore. Image encryption is an important research direction in information security. As an important way of expression in multimedia information, images are widely used in various fields due to their vivid and intuitive features. [0003] Image encryption originated from the early classical encryption theory, and its purpose is to hide the real information of the image itself, so that the thief cannot obtain the original image after obtaining the ciphertext, and the authorized receiver can use the pre-agreed key and ...

AI Technical Summary

Problems solved by technology

However, most of the typical image encryption systems based on transformations are linear systems, which are weak against attacks compared with nonlinear encryption systems

This is because the functional relationship between plaintext, ciphertext, and key in a linear encryption system is relatively simple, which cannot effectively resist common attacks such as chosen plaintext attacks and known plaintext attacks.

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