Electronic timestamping: definition and usage

Electronic timestamping in a nutshell

Electronic timestamping links a digital document to a precise date and time in a verifiable and tamper-proof manner. It is proof that a document existed at a given moment — decisive evidence in case of 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 written in the document matches the actual signature

For a contract worth €50,000 signed on 30 December: in the current or following financial year?

How timestamping works

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

• Receives the cryptographic fingerprint of the document

• Adds the precise date and time (NTP clock)

• Signs the whole thing with its own key

• Returns a timestamping token

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

Simple vs qualified timestamping

eIDAS distinguishes two levels:

• Simple: any service provider. Useful proof but without legal presumption.

• Qualified: QTSP registered on the trust list. Legal presumption of reliability (article 41 eIDAS).

For high-value documents, qualified timestamping is recommended.

When to use timestamping

Timestamping is systematic in modern electronic signatures. But certain situations require particular attention:

• Call for tenders (submission deadline)

• Intellectual property (date of creation)

• High-stakes contracts (tax year)

• Share transfers (transfer date)

• Regulatory filings (CNIL, ACPR, AMF)

Proof of existence and integrity

Timestamping proves two things:

• Existence: the document existed at date T

• Integrity: no modification since T

How to verify a timestamp

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

How Certyneo helps you

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

FAQ

Is a system timestamp enough?

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

Do I have to pay for qualified timestamping?

Generally included in professional plans on signature platforms.

Does timestamping expire?

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

Does timestamping replace signature?

No. Signature identifies the author, timestamping proves the moment. Complementary.

Can I timestamp without signing?

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

Conclusion

Timestamping is the seatbelt of electronic signature: invisible in everyday use, essential in case of accident.

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