Color image encryption method and device

Abstract

The invention discloses a color image encryption method and device, and the method comprises the steps: a color image being coded into a first quaternion matrix; dividing the quaternion matrix into non-overlapping sub-blocks, and performing modulation and quaternion Gyrator transformation on each sub-block to obtain a second quaternion matrix; extracting a real component, a first imaginary component, a second imaginary component and a third imaginary component of the second quaternion matrix, and constructing to obtain a first complex matrix and a second complex matrix; carrying out multi-resolution decomposition on the first complex matrix and the second complex matrix to obtain an approximate component and a detail component, and recombining to obtain a third complex matrix and a fourthcomplex matrix; and performing Gyrator transformation with an angle of beta on the third complex matrix and the fourth complex matrix to obtain a first ciphertext image and a second ciphertext image respectively. According to the method, the complexity of a single-channel processing mode is effectively avoided, meaningful content of the image can be hidden, and the method can be applied to the field of multimedia information security.

Description

technical field [0001] The invention relates to the technical field of image encryption, in particular to a color image encryption method and device. Background technique [0002] With the continuous development of image acquisition equipment, more and more color images appear in people's daily life and work. On the one hand, the information presented by these images may contain personal privacy, and is transmitted through the Internet, facing the problem of being illegally disseminated and used. On the other hand, these images can also be easily tampered with using freeware. Therefore, the security of image information is facing great challenges. [0003] For color image encryption, existing grayscale image encryption methods can be used. For example, the color image encryption method based on the index format, this method represents the color image as an integer matrix and a color mapping matrix, and treats the integer matrix as a grayscale image. But this preprocessin...

AI Technical Summary

Problems solved by technology

For example, Panna and others proposed a color image encryption method based on image sub-block fractional Fourier transform and wavelet transform. This method treats each color component as a grayscale image. The encryption process is not only cumbersome, but also the ciphertext requires a large storage

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