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Chi-square attack

Definition

A specific steganalysis test for LSB substitution in images. It tests whether pairs of pixel values that are related by flipping the LSB (called PoVs, pairs of values) appear with equal frequency, which they will when LSB substitution has been applied across the image.

Related terms

Adaptive embedding
A steganographic strategy that concentrates embedding changes in high-texture or high-noise image regions where they are perceptually and statistically harder to detect....
Calibration
A steganalysis technique that estimates the cover image statistics by cropping or decompressing and re-compressing the test image to produce a reference....
Convolutional steganalysis network
A deep neural network trained end-to-end to classify cover versus stego images. Architectures such as XuNet, SRNet, and Yedroudj-Net use learned high-pass...
LSB substitution
Least-significant-bit substitution: the lowest-order bit of each sample value (pixel colour channel or audio sample) is overwritten with one bit of the...
Rich model (SRM)
A high-dimensional feature set for steganalysis constructed from joint statistics of pixel prediction residuals computed with many different filter kernels and quantisation...

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