Verify file integrity with a SHA-256 hash
Get the SHA-256 fingerprint of any file and check it against a hash you received, to prove the file is exactly the same — bit for bit.
The hash is calculated inside your browser: the file is not uploaded anywhere. Free and unlimited.
How to check the SHA-256 hash of a file
Drop one or more files — PDF, Word, images, archives, any type. RoseLab shows the SHA-256 hash of each one, with a button to copy it. To verify a file, paste the expected hash into the check field: if one of your files matches, it is marked as intact.
A SHA-256 hash is a 64-character fingerprint. Change a single comma in a document and the hash changes completely, which is why it is used to prove that a file has not been tampered with.
When you need to prove a document was not altered
Record the hash of a contract when it is signed and you can later prove that the copy someone presents is, or is not, the same file. Check that a download matches the checksum published by its author. Confirm that the file you received by email is identical to the one in the case record. RoseLab comparison reports print the hash of each compared file, and this page is where anyone can check them.
A matching hash proves integrity — that the file is identical. It does not, by itself, prove who created the file or when; for that you need a digital signature or a timestamp.
Frequently asked questions
What is a SHA-256 hash?
It is a fixed-length fingerprint of a file. Identical files always have the same hash; any change produces a completely different one.
How do I know if a PDF was modified?
Calculate its SHA-256 hash here and compare it with the original hash. If they match, the file is unchanged.
Is my file uploaded to calculate the hash?
No. The calculation happens in your browser, so you can check confidential files safely.
Which file types are supported?
Any type: PDF, Word, Excel, images, videos, ZIP archives and more.