Robust multiple color images encryption using discrete Fourier transforms and chaotic map

Based on discrete Fourier transforms and logistic-exponent-sine map, this paper investigates an encryption algorithm for multiple color images. In the encryption process, each color image represented in trinion matrix is performed by block-wise discrete trinion Fourier transforms. Then the first real matrix is constructed by splicing real and imaginary parts of transformed results. Followed by two-dimensional discrete Fourier transform, the second real matrix is synthesized only using half of the spectrum on the basis of the conjugate symmetry property. In order to further enhance the randomness of interim result, the random multi-resolution singular value decomposition is exploited. Afterwards, a sharing process is utilized to get final cipherimages. Numerical simulations performed on 300 color images have shown that quality of correctly decrypted images is much better, where the PSNR value is up to 305.03 dB. The number of changing pixel rate and unified average changing intensity are respectively greater than 99.99% and 33.33%, indicating good sensitivity. The comparison with other methods under noise and cropping attacks validates the reliability of the proposed algorithm.

Automated summary

This paper proposes an encryption algorithm for multiple color images based on discrete Fourier transforms and logistic-exponent-sine map. Through block-wise processing and random multi-resolution singular value decomposition, the randomness of the encrypted result is enhanced. Numerical simulations show that the algorithm produces high-quality decrypted images with high PSNR values, and demonstrates good sensitivity to pixel changes and intensity changes.