High-capacity image steganography method and a secret information extraction method

Abstract

The invention discloses a high-capacity image steganography method. The method comprises the following steps: carrying out scrambling processing on a carrier image; Dividing the scrambled image into N* N sub-blocks and carrying out DCT (Discrete Cosine Transform); Classifying each DCT block, and selecting an embedded block; Element values at selected positions are extracted from a matrix obtainedafter the DCT coefficient of each embedded block is scanned in a Z shape, and a coefficient matrix is obtained; Extracting element values which are the same as the element values at the selected positions from a matrix obtained after Z-shaped scanning of the Q table to form a quantization matrix; Calculating a division matrix and block capacity through the quantization matrix; Dividing the bit stream of the secret information according to the block capacity; Calculating an embedded matrix for the divided bit stream; Calculating a new coefficient matrix; Replacing the DCT coefficient with theelement value in the new coefficient matrix, and carrying out inverse operation of Z-shaped scanning to obtain a new DCT coefficient; And carrying out DCT inverse transformation on each sub-block andthen carrying out inverse scrambling processing. The invention also discloses a secret message extraction method. And the image complexity is high and the embedding capacity is large.

Description

technical field [0001] The invention relates to the image field, in particular to a large-capacity image steganography method and a secret information extraction method. Background technique [0002] Information hiding is from the perspective of hiding the existence of information, ensuring the security of secret information transmission, using the limitations of human senses, embedding secret information in the multimedia carrier for public transmission, so that the third party cannot detect the existence of secret information . Information hiding is divided into multiple branches such as steganography, numerical watermarking, information sharing, and hidden channels. From the initial military field, it has been applied to many fields such as commercial information, government confidential information, and personal sensitive information. [0003] Commonly used image steganography techniques can be divided into two categories: Steganography techniques based on spatial domai...

AI Technical Summary

Problems solved by technology

In general, the spatial domain steganography algorithm is simple and the amount of information hidden is large, but the main disadvantage is that the robustness to most attacks is not strong, and the hidden algorithm is easy to be detected; the robustness of the steganographic technology based on the transformation domain Among them, the DCT domain is the most widely used transform domain algorithm, but the biggest disadvantage of the current transform domain algorithm is that the amount of embedded information is small and the extraction is complicated.

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