Verification of the authenticity of a document
Deposit a file to see if it was sealed in a Certyneo evidence safe and when.
No file uploaded: only its SHA-256 signature, a one-way identifier, is used for verification.
How does it work?
Local footprint
Your browser is calculating the SHA-256 signature of the file.
Comparison to the chest
The print is being compared to the documents sealed in the Certyneo evidence safe.
Proof of date
If a match exists, we indicate the earliest date of sealing, which is reliably timestamped.
What does this verification prove?
A digital document can be copied, modified or forged without leaving any visible trace — a date changed, a clause rewritten, a page added. Verification by SHA-256 fingerprint makes it possible to know, in a few seconds and without sending the file, whether a PDF matches exactly the original sealed in a legally-binding safe or signed via Certyneo. Even the slightest modification, even of a single character, completely changes the fingerprint: an exact match is therefore proof of integrity, not merely a presumption. This check is useful before signing a contract received by e-mail, to verify that a payslip, quotation or statement has not been altered, or in case of dispute over the version of a document originally sent. Documents sealed in the Certyneo safe also benefit from RFC 3161 electronic timestamping and storage in WORM mode (Write Once Read Many), which prevents any further modification, even by Certyneo.
Verify a document, in detail
What the verification proves, and what it does not prove.
How to verify that a document has been electronically signed with Certyneo?
Drop the PDF file in the verification area above, or click to select it. Your browser calculates its SHA-256 fingerprint and compares it to documents sealed or signed in Certyneo. If a match exists, the page displays the signature level, the number of signatories and the completion date, in a few seconds and without creating an account.
Is the file I drop sent to a server?
No. Only its SHA-256 fingerprint, calculated locally by your browser using the Web Crypto API, is transmitted to Certyneo. The file content never leaves your device, and the fingerprint alone does not allow the document to be reconstructed.
What is a SHA-256 fingerprint and why use it to verify a document?
SHA-256 is a cryptographic hash function that transforms any file into a sequence of 64 characters unique to its exact content. Changing a single character in the document completely changes its fingerprint: comparing two fingerprints therefore makes it possible to know whether two files are strictly identical, without ever comparing their content.
What does "no match" mean during verification?
This means that the fingerprint of the file submitted does not match any document sealed in the Certyneo safe or any finalized signature on the platform — either because the document was never deposited there, or because it has been modified since, even slightly, compared to the original version.
Is this verification free and accessible without an account?
Yes. Verification of a document is a free public service of Certyneo, accessible without registration or login. Only the initial deposit of the document in the safe or its electronic signature requires a Certyneo account.
What is the difference between a document "sealed" in the safe and a document "signed"?
A document sealed in the legally-binding safe is simply deposited and timestamped, without any signatory affixing an electronic signature to it: this proves its existence and integrity at a given date. A signed document has followed a Certyneo electronic signature process, with one or more identified signatories and a simple, advanced or qualified signature level.
Can I share the result of this verification with a third party?
Yes. Each file verification generates a permanent address in the format /verifier-un-document?sha256=… corresponding to the document's fingerprint. You can transmit this link to a third party — notary, lawyer, partner — who will find the same result without needing the original file.
Is the result of this verification admissible in case of dispute?
SHA-256 fingerprint matching demonstrates file integrity compared to the version sealed or signed in Certyneo. For documents sealed in the safe or signed at an advanced or qualified level, this technical proof is accompanied by a deposit certificate or an audit trail, available from your Certyneo space.
Complete the verification
The digital safe with probative value and Certyneo electronic signature, before any audit.
Any doubt about the integrity of your documents?
The Certyneo digital safe seals each document, dates it and keeps it in unalterable WORM mode, with a revocable deposit certificate.