BMP Steganography Extractor
Extract hidden data from BMP files. Supports pixel LSB, palette index, and reserved field methods. Auto-detect mode for CTF challenges.
Try the demo instantly
Loads a BMP with a hidden message already embedded
Drop a BMP here or click to browse
24-bit or 8-bit uncompressed BMP · Max 50 MB
100% Client-Side Processing
Your BMP is processed entirely in this browser tab. Nothing is uploaded to any server.
How to Extract Hidden Data from a BMP (5 steps)
- Upload the BMP image that may contain hidden data
- Select extraction method (Auto-detect recommended)
- Adjust bit depth if you know how it was encoded
- Enter password if the data was encrypted
- Click Decode to extract the hidden payload
Frequently Asked Questions
How does auto-detect work?
Auto-detect tries Pixel LSB (1-bit and 2-bit), Palette LSB, and Reserved Bytes in sequence. It looks for our stego header and validates the extracted data.
What if I know the bit depth used?
If you know the exact bit depth (1-8) used during encoding, select Manual mode and set it explicitly. This ensures precise extraction without trial-and-error.
The decoder says 'encrypted' but I don't have a password?
The data was encoded with AES-256 encryption. Without the correct password, you can only see the encrypted bytes, not the original content.
Can this extract data hidden by other BMP stego tools?
Possibly. This decoder looks for our header format but also attempts raw LSB extraction. Tools using standard pixel LSB may be compatible.
Why does extraction fail for compressed BMPs?
Compressed BMPs (RLE-encoded) alter the pixel data structure. This tool requires uncompressed BMPs. Convert to uncompressed BMP first.
I see random data. How do I know if something is hidden?
Random-looking data could be encrypted (try a password), compressed, or noise. Check the entropy value — high entropy (>7.0) suggests encryption; low entropy with low printable ratio suggests noise.