Advanced Signature (AES / eIDAS level 2)
Definition
The four requirements of Article 26 eIDAS:
• Unique link to the signatory: the signature can only be attributed to one person — ensured by the identification channel (named email, personal mobile).
• Signatory identification: the process makes it possible to find out who signed — declared identity information, email address, mobile number verified by OTP code.
• Exclusive control: signature creation data is under the control of the signatory alone — materialized by strong authentication at the time of signing.
• Integrity: any subsequent modification of the document is detectable — guaranteed by cryptographic sealing (hashing + PAdES).
AES vs SES vs QES: SES requires no enhanced verification (checkbox, drawn signature) — sufficient for everyday documents; AES adds strong authentication and proof of integrity — suited to employment contracts, mandates, leases, banking and insurance files; QES adds a qualified certificate issued after identity verification and a certified device (QSCD) — it is the legal equivalent of a handwritten signature throughout the EU, required for the most sensitive acts.
Legal value: Article 25 of eIDAS prohibits refusing legal effect to a signature solely on the ground that it is electronic, and Article 1367 of the Civil Code recognizes it provided that a reliable process identifies the signatory and guarantees the integrity of the deed. In case of dispute, the reliability of AES is demonstrated by the bundle of evidence: timestamped audit trail, recorded OTP codes, document fingerprint, time stamp. QES additionally benefits from a presumption of reliability (burden of proof reversed).
When is AES sufficient? Employment contracts and amendments, commercial contracts, quotations and purchase orders, mandates (sale, property management, SEPA), leases, KYC and credit files: AES is the market standard. Switch to QES for authentic deeds, certain public procurement, sale of business goodwill, or when a text requires it.
On Certyneo: AES is available on all paid plans — the signatory is authenticated by SMS OTP, the signed PDF is sealed in PAdES format with time stamp, and the complete audit trail is attached to the document. QES is available per signature, with no dedicated subscription. Understand the three eIDAS levels → · The eIDAS regulation in detail →
Frequently asked questions
What is an advanced electronic signature (AES)?
It is the second of the three signature levels defined by the eIDAS regulation. It must be uniquely linked to the signer, allow their identification, be created under their sole control and make any subsequent change to the document detectable (art. 26). In practice it combines strong signer authentication, cryptographic sealing of the document and a timestamped audit trail.
What is the difference between an advanced and a qualified signature?
The qualified signature (QES) takes all the requirements of the advanced one and adds two guarantees: a qualified certificate issued after the signer's identity has been verified by a qualified trust service provider (QTSP), and a certified signature-creation device (QSCD). In return, the QES enjoys a legal presumption: it is the equivalent of a handwritten signature throughout the EU, whereas the advanced signature must demonstrate its reliability in the event of a dispute.
What is the legal value of an advanced signature?
An advanced signature is fully valid: article 25 of eIDAS prohibits denying it legal effect solely because it is electronic, and it is recognised as soon as a reliable process identifies the signer and guarantees the integrity of the document. The audit trail, the OTP code and the cryptographic seal form precisely that body of evidence.
When is an advanced signature enough?
AES is the recommended level for the vast majority of B2B and HR documents with real stakes: employment contracts, commercial contracts, mandates, leases, banking or insurance files. QES remains required or advisable for the most sensitive deeds: notarial acts, certain public procurement documents, business transfers, or wherever the law requires an authentic instrument.
How do I create an advanced electronic signature?
Upload your document to an eIDAS-compliant platform, designate the signers and choose the advanced level: each signer is then authenticated by OTP code (via SMS at Certyneo) before signing, the document is cryptographically sealed and the complete audit trail is attached to the signed PDF. No installation or certificate to purchase for the signers.
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