Signature Proof Log: What Is It For?

What is a proof log

The proof log (or audit trail) is the time-stamped journal of all actions performed on an electronic signature document: sending, opening, OTP entry, signing, refusal, expiration.

It is the equivalent of a digital "logbook", which constitutes the main enforceable evidence in case of dispute.

Typical content

Each recorded event includes:

• precise date and time (usually qualified time-stamping)

• action (sending, opening, OTP sent, OTP entered, signing, refusal)

• actor (signatory, system)

• IP address of the signatory

• user-agent (browser and OS used)

• metadata (document size, fingerprint, etc.)

The proof log before the judge

French courts recognise the proof log as a determining factor in case of dispute, provided that it is:

• produced by an eIDAS-compliant platform

• complete and consistent

• time-stamped by a trusted third party

• preserved according to legal periods

The combination of proof log + PDF signed with cryptographic fingerprint makes good faith contestation extremely difficult.

Where to find the log

Two typical locations:

• Integrated into the PDF: often on the last page, visible summary

• Accessible via the platform: detailed audit trail exportable

Some platforms provide a public verification link allowing anyone to consult the log without an account.

Practical use

In internal audit

• verify signature compliance

• check date consistency

• identify anomalies (unusual IP, suspicious times)

In disputes

• produce the log as evidence before the court

• refute a signature contestation

• establish precise chronology

In regulatory control

• URSSAF, labour inspection, CNIL

• export of the log for affected contracts

Best practices

• Keep the log for the entire legal life of the document

• Export periodically to avoid platform dependency

• Never modify the log manually (invalidates evidence)

• Train your legal teams in log use

Common mistakes

• Keep only the PDF, not the log

• Store the log in a non-exportable proprietary format

• Forget to include qualified time-stamping

• Fail to anonymise logs when transmitting to third parties

Concrete case: signature contestation

An employee being dismissed contests having signed his non-compete amendment. The employer produces the proof log:

• precise date: 15 March 2024, 14:32

• IP: consistent with home location

• OTP SMS entered on the employee's phone (number in his file)

• PDF fingerprint unchanged since

The labour court rejects the contestation — proof log decisive.

How Certyneo helps you

Certyneo automatically generates a complete proof log for each signed envelope. Exportable in PDF or JSON, integrated into the final PDF, kept for 10 years, and available via public verification link for third parties.

Discover the Certyneo electronic signature solution

FAQ

Is the log admissible in court?

Yes, provided it is produced by an eIDAS-compliant platform.

Can I modify the log?

No, any modification makes it invalid.

How long should I keep it?

At least as long as the signed document (10 years for commercial contracts).

Does the log reveal personal data?

Yes (IP, user-agent, times). Protect its access according to GDPR.

Can I share it with a third party?

Yes, via a verification link or PDF export.

Conclusion

The proof log is the legal key to electronic signature. Keep it carefully, and you will have a solid position against any contestation.

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