Proof of signature log: what is it for?

What is a proof log

The proof log (or audit trail) is the timestamped log of all actions carried out on a electronic signature document: sending, opening, OTP entry, signing, refusal, expiration.

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

Typical content

Each recorded event includes:

• precise date and time (generally a qualified timestamp)
• action (sending, opening, OTP sent, OTP entered, signing, refusal)
• actor (signer, system)
• IP address of the signer
• user-agent (browser and OS used)
• metadata (document size, hash, etc.)

The proof log before a judge

French courts recognize the proof log as a decisive element in the event of litigation, provided that it is:

• produced by an eIDAS-compliant platform
• complete and consistent
• timestamped by a trusted third party
• retained for the legal retention periods

The combination of proof log + signed PDF with cryptographic hash makes a good-faith dispute of the signature extremely difficult.

Where to find the log

Two typical locations:

1. Embedded in the PDF: usually on the last page, visible summary
2. Accessible via the platform: detailed, exportable audit trail

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

Practical use

In internal audits

• verify signature compliance
• check date consistency
• identify anomalies (unusual IP, suspicious times)

In litigation

• produce the log as evidence before the court
• refute a signature dispute
• establish a precise timeline

In regulatory audits

• URSSAF, labor inspectorate, CNIL
• export the log for the contracts concerned

Best practices

• Keep the log for the entire legal retention period of the document
• Export periodically to avoid dependency on the platform
• Never modify the log manually (invalidates the evidence)
• Train your legal teams on using the log

Common mistakes

• Keeping only the PDF, not the log
• Storing the log in a proprietary, non-exportable format
• Forgetting to include the qualified timestamp
• Failing to anonymize logs when transmitting them to third parties

Concrete case: contested signature

A dismissed employee disputes having signed his non-compete amendment. The employer produces the proof log:

• precise date: March 15, 2024, 2:32 PM
• IP: consistent with home address
• SMS OTP entered on the employee's phone (number on file)
• PDF hash unchanged since

The labor tribunal rejects the challenge — the proof log is decisive.

How Certyneo helps you

Certyneo automatically generates a complete proof log for each signed envelope. Exportable as PDF or JSON, embedded in the final PDF, retained for 10 years, and available via a 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 a platform compliant with eIDAS.

Can I modify the log?

No, any modification renders it invalid.

How long should it be kept?

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

Does the log reveal personal data?

Yes (IP, user-agent, times). Its access must be protected in accordance with GDPR.

Can it be shared 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 dispute.

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