Electronic time stamping: definition and use

Timestamping in a nutshell

Electronic timestamping (timestamping) links a digital document to a precise date and time, in a verifiable and tamper-proof way. It is proof that a document existed at a given moment — a decisive argument in the event of a dispute over the date of a commitment.

Why timestamping is crucial

Without timestamping, it is impossible to prove:

• whether a contract was signed before or after a key event
• who last modified the document
• whether the date shown in the document matches the actual signing

For a €50,000 contract signed on December 30: does it fall within the current fiscal year or the next?

How timestamping works

The standard process relies on a timestamping authority (TSA) which:

1. Receives the document's cryptographic hash
2. Adds the precise date and time (NTP clock)
3. Signs the whole with its own key
4. Returns a timestamp token

This token is embedded in the PDF in PAdES format. Anyone can then verify the date and integrity.

Simple vs. qualified timestamping

eIDAS distinguishes two levels:

• Simple: any provider. Useful evidence but without legal presumption.
• Qualified: a QTSP listed on the trust list. Legal presumption of reliability (Article 41 of eIDAS).

For high-value documents, a qualified timestamp is recommended.

When to use timestamping

Timestamping is systematic in a modern electronic signature. But certain situations call for particular vigilance:

• Tenders (submission deadline)
• Intellectual property (date of creation)
• Contracts with significant tax implications (accounting period)
• Share transfers (transfer date)
• Regulatory filings (CNIL, ACPR, AMF)

Proof of existence and integrity

Timestamping proves two things:

1. Existence: the document existed at date T
2. Integrity: no changes since T

How to verify a timestamp

Adobe Reader → signature properties → timestamp authority details. Displays the TSA name, exact date, and validity status. Tools such as pdfsig allow command-line verification.

How Certyneo helps you

All Certyneo signatures include a timestamp in PAdES format. For cases requiring a qualified timestamp, we interface with European eIDAS-qualified TSAs.

Discover Certyneo's electronic signature solution

FAQ

Is a system timestamp enough?

No. A local timestamp can be altered. Only a trusted third party has evidentiary value.

Do you have to pay for a qualified timestamp?

Generally included in the professional plans of signature platforms.

Does a timestamp expire?

The token itself does not expire, but its long-term validity depends on the algorithms used. Use PAdES-LTA for multi-decade validity.

Does timestamping replace signing?

No. The signature identifies the author, the timestamp proves the moment. They are complementary.

Can I timestamp without signing?

Yes, to prove existence at a given date (digital INPI filing, proof of precedence).

Conclusion

Timestamping is the seatbelt of electronic signature: invisible day to day, indispensable in the event of an incident.

Try Certyneo to send, sign and track your documents online simply, quickly and securely.