LSB steganography extractor
Extract least-significant-bit data from images across every channel, bit order, and traversal direction, with bit-plane visualisation.
Open in ctfpalChanging the last bit of a colour channel shifts that channel’s value by one out of 256 - invisible to the eye, and eight pixels of a colour image carry three bytes of hidden data. It is the most common image steganography technique because it is easy to implement and genuinely imperceptible.
The parameter space is the whole difficulty
Extraction is trivial once you know how the data was written, and there are many ways to write it: which channels (R, G, B, A, or combinations), how many bits per channel, whether pixels are read row-first or column-first, and whether bits are packed most- or least-significant first. That is dozens of combinations, and only one produces readable output.
- Channels - RGB in order is most common; alpha-only is a favourite trick because the image looks completely normal.
- Bit order - MSB-first and LSB-first both appear. Wrong order gives text that is almost readable, with characters scrambled in a regular pattern.
- Traversal - row-major is standard; column-major appears in challenges written to defeat naive tools.
- Depth - one bit per channel is standard, two is used when more capacity is needed and starts to be faintly visible.
Part of a module
8. Steganography
Sweep an image, audio file, or paragraph for hidden data across the whole technique space rather than guessing one method.
Practise on real challenges
Go deeper
- A workflow for image steganography, from magic bytes to bit planesStego challenges reward order, not inspiration. The sequence that finds the payload: container checks before pixel checks, structure before statistics, and the specific tells that separate a PNG trick from a JPEG one.
Related tools
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