SHA-256 Evidence Hash Checker

Check that a file has not changed since it was captured. Drop in a photo, video, PDF or export and get its SHA-256 hash. Paste a recorded hash to compare. Your file never leaves your device.

How to use it

1. Hash the file. Drop it in. The SHA-256 appears in a few seconds. Large videos take longer.
2. Compare. Paste the hash that was recorded when the file was captured. You get a clear match or no match.
3. Keep a record. Download the CSV. It lists each file name, size, hash and the UTC time of the check.

What a hash tells you

A SHA-256 hash is a 64 character fingerprint of a file's exact bytes. Change one pixel, one frame or one letter and the hash changes completely.

If the hash recorded at capture matches the hash of the file you hold now, the file has not been altered in between. That is the integrity part of a chain of custody.

Questions

Is my file uploaded?

No. Your browser does the maths on your device. The file is never sent to us or anyone else.

Does a match prove the content is genuine?

No. A match proves the file is bit for bit identical to the one that produced the recorded hash. It does not prove who made the content or that what it shows is true.

Why SHA-256 and not MD5?

MD5 and SHA-1 have known collision attacks, so two different files can be made to share a hash. No practical collision attack is known for SHA-256.

Does it work offline?

Yes. Once this page has loaded you can disconnect and it keeps working.

Is there a size limit?

No set limit. Big files are read in chunks so memory stays low. Speed depends on your device.

Link to this tool

Free to link from a resource page, guide or course. Copy this: