Document certificates
Create a tamper-evident certificate for any file. Anyone can re-hash the original and confirm it still matches — no “I never got that” disputes.
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What it can do
A document certificate records a cryptographic fingerprint of your file at a point in time. Share the verification link with clients, counterparties, or auditors.
- SHA-256 hash of the file — the file itself never needs to leave your machine for client-side checks.
- Public verification page — a durable link that shows what was certified and when.
- Works on any file type — contracts, invoices, designs, PDFs, zips.
- Optional Bitcoin timestamping — stronger independent proof for accounts that enable it.
Who it’s for
Anyone who sends important documents and needs a simple way to prove the exact bytes that were delivered — freelancers, agencies, and small legal/ops teams.
What it is not
This is not an e-signature product and not legal advice. It proves integrity of a file’s contents, not that a person legally signed a contract.
Try it in Tools
Hash a file in your browser, or open Certificates in the app to issue a full certificate.
Open file hash checker → Create a certificate in appFAQ
Do you store my document?
Certification is based on the file hash. You control what you upload; verification compares hashes against the recorded fingerprint.
Is this the same as SSL certificates?
No. Document certificates prove file integrity. SSL/TLS certificates secure a domain’s HTTPS — see the SSL product page for that.