Steganography methods in images

Question

Steganography

If anyone knows some methods, then write and, if possible, attach a link to an adequate description of the algorithm.
P.S. Algorithms ala replacement of the last bits I ask not to offer.

Answer 1

I would like to implement one of the methods for hiding information in a bmp file.

Answer 2

I remembered the LSB method (Least Significant Bit, the least significant bit). The bottom line is the redundancy of the image. The human eye can recognize no more than 5 bits of color in each pixel channel, while even a butterfly cannot recognize the last 3 bits (they have super-sensitive organs of vision). Actually, these 3 bits can be changed as you like. Each pixel in RGB has 3 channels, respectively 3*3*number of pixels=message volume. Simple calculations show that up to 900Kb of information can be stored in a 1024*800 stegocontainer.
The main disadvantages are that when there is noise in the communication channel, the steganocontainer is destroyed; in general, the steganocontainer is unstable to any attacks.

Answer 3

Q-transform was remembered. There is no link, so on the fingers.
The algorithm is something like this:
Suppose we have a 24-bit image

1. We translate from RGB to YCrCb (brightness, chromatic red and blue).
2. Sampling. We split the image into 8x8 matrices. From each such we form 3 working DCT matrices - 8 bits separately for each component.
3. We apply DCT to each matrix. As a result, there will be a matrix with low-frequency components of the image in the upper-left corner and high-frequency components in the lower right.
4. The actual quantization is element-wise.
5. In this matrix, in a zigzag order ((0,0) (1,0) (0, 1) (2, 0) (1, 1) (0, 2)...), that is, from low to high frequencies, you can enter text. only without fanaticism.

Answer 4

Cutter-Jordan-Bosson method (the "cross"
method) Koch-Zhao method (modifications: Bengam-Mimon-Eo-Jung method, Hsu-Wu method)
PS I don't know where to read about it on the Internet, they read steganography at my university .

Answer 5

Cutter-Jordan-Bossen method habrahabr.ru/blogs/algorithm/115287/