Elysia Tools
Navigation
Utilities
Identify file types by their magic numbers (file signatures)
Execution
Fill in the form, run the tool, and review the result in one place.
Samples
Related
Ready for a run
Tool usage guide
The Magic Number Detector is a precise utility designed to identify file types by analyzing their unique file signatures, commonly known as magic numbers. By inputting the hexadecimal header sequence, you can instantly verify the true format of a file regardless of its extension.
Background
A user sent a file named 'data.txt' that failed to open in a text editor.
Problem
The file extension suggests a text file, but the content appears to be binary data.
How to use
Extract the first 4 bytes of the file using a hex editor and input them into the detector.
50 4B 03 04Outcome
The tool identifies the signature as a ZIP archive, confirming the file was mislabeled.
Background
An uploaded image on a website is not rendering correctly in the browser.
Problem
Need to confirm if the file is a valid JPEG or if the header is corrupted.
How to use
Input the standard JPEG header signature into the detector.
FF D8 FFOutcome
A magic number is a constant numerical or text value used to identify the file format or protocol of a file, typically located in the first few bytes of the file header.
No, the tool accepts both space-separated hex strings (e.g., 50 4B 03 04) and continuous strings (e.g., 504B0304).
It can identify any file type that has a standardized, well-documented magic number signature.
The tool processes the signature string locally; no actual files are uploaded or stored.
If the result differs from your extension, it indicates the file has been renamed or mislabeled, which is a common tactic in obfuscation or a sign of a corrupted header.
The tool confirms the signature matches JPEG, helping isolate the issue to the image data rather than the file format.