The invention relates to the technical field of image
encryption, and discloses an
image steganography method and
system based on dynamic latent variables and
frequency domain embedding, and the method comprises the steps: obtaining a hash value and a plurality of secret keys of a to-be-encrypted color
plaintext image; constructing a hyperchaotic
system, and iteratively generating a plurality of key streams; a to-be-encrypted color
plaintext image is decomposed into R, G and
B channel matrixes, and three
ciphertext sequences are obtained based on the three channel matrixes; the method comprises the following steps: initializing a
noise image, determining a
time step by using a secret key, and executing reverse denoising of a denoising
diffusion implicit model (DDIM) with a fixed step length to obtain an intermediate
latent variable; based on the intermediate
latent variable and the three
ciphertext sequences, obtaining a dense
frequency domain-containing sub-band, and performing
inverse discrete wavelet transform on the low-frequency sub-band and the dense
frequency domain-containing sub-band to obtain a dense
latent variable; and executing DDIM denoising of the
time step by taking the secret-containing latent variable as a starting point to obtain a secret-containing image. By adopting the method, the security and visual quality of
image steganography can be improved, and high embedding capacity is ensured.