◈ Check a file
Does this file match what was recorded?
Drop it in. The check runs in your browser and the answer takes a few seconds.
- Free
- No account
- Nothing to install
Check a file
free · no account · nothing to installFingerprinted in your browser — only the fingerprint is sent. A fingerprint is not encryption; predictable inputs can be tested against it.
What this searches.
This looks up the computed or supplied fingerprint among eligible public Quantum Notary service records. It does not search every service record or the whole Base chain. No match alone does not establish that a file changed.
Files recorded with us.
Eligible public Quantum Notary service records. You do not need an account to look up a fingerprint. This does not search every service record.
The rest of the blockchain.
This is not a search of Base, or of any chain. A file timestamped through some other service will not turn up here.
Sixty-four characters, exactly.
The fingerprint computed or supplied in this browser against eligible records. No match alone does not establish that a file changed; a supplied hash does not check a file.
A match hands you the Base transaction reference and the position of your fingerprint inside it, so you view the block directly on Base explorer.
You can run this check without us.
- Keep the exact original file, unaltered.
- Open the transaction your receipt names on any public Base explorer.
- Read the 32 bytes at the position the receipt gives, and compare them with the fingerprint of your file.
What that path still depends on
The exact file, byte for byte. Re-saving can change its fingerprint if the bytes change.
The receipt, which names the transaction and the position inside it.
Somebody serving Base history. Not us — this path uses no API of ours and no record of ours.
What survives if we disappear →▸ How to check a file
How to check whether a file matches a record
Hash the file you are holding and look for eligible public Quantum Notary service records. This does not search the whole Base chain. Independent checking uses your receipt and Base data.
What you need
- The file, exactly as it was recorded. A re-saved copy will not match if its bytes change.
- No account, and nothing to install.
- The receipt, if you want to read the transaction from Base yourself.
The whole procedure, start to finish
Download the independent Base verifier
Keep this package with your exact file and receipt or proof JSON. It includes the required code and a README, needs Python 3.12+, and checks Base history without the Quantum Notary API. No account or source checkout is needed.