Glossary
What is an advanced electronic signature?
Short answer
An advanced electronic signature is the middle of the three eIDAS levels. It must be uniquely linked to and able to identify the signer, made with signature creation data the signer controls with a high level of confidence, and linked to the document so that any later change can be detected. In practice it usually means a certificate-based signature issued after the signer's identity has been checked.
Updated 25 October 2026
- Advanced electronic signature
- An advanced electronic signature (AES) is an electronic signature that meets the four requirements of eIDAS Article 26: it is uniquely linked to the signatory, capable of identifying them, created with data under their sole control, and linked to the signed data so any later change is detectable.
The four requirements in Article 26
eIDAS Article 3(11) defines an advanced electronic signature as one that meets the requirements in Article 26. They are:
- (a) it is uniquely linked to the signatory
- (b) it is capable of identifying the signatory
- (c) it is created using electronic signature creation data that the signatory can, with a high level of confidence, use under their sole control
- (d) it is linked to the data signed in such a way that any subsequent change in the data is detectable
How advanced signatures are usually made
Most AES products issue the signer a certificate, or a short-lived one generated on the spot, after an identity check such as a passport scan or a bank ID login. The signer's key, held on a device or in a remote signing service, creates a digital signature over the document.
Requirement (d) is met by the cryptography: change the file and the signature no longer verifies. Requirements (a) to (c) depend on the identity check and on keeping the key under the signer's control.
Advanced versus simple and qualified
A simple electronic signature has no technical requirements. A qualified electronic signature is an advanced one that also uses a qualified certificate from a trust service provider on an EU trusted list and a qualified signature creation device. Only the qualified level gets automatic equivalence to a handwritten signature under Article 25(2).
The advanced level is useful where you want strong proof of identity without the cost and setup of qualified signatures, such as some HR documents in countries that ask for more than a simple signature.
Why Sign PDF signatures are not advanced
Sign PDF's tamper-evident seal satisfies something like requirement (d) for the document as a whole, but the key belongs to Sign PDF, not to the signer, and we verify signers only by an email code, not by checking ID. So our signatures are simple electronic signatures, not advanced ones. If you need AES, choose a provider that offers identity verification and signer certificates. This is not legal advice.
Questions people ask
Is an advanced electronic signature legally equal to a handwritten one?
Not automatically. It is admissible and carries more evidential weight than a simple signature, but only a qualified signature has automatic equivalence under eIDAS Article 25(2).
Does an advanced signature need ID verification?
eIDAS does not prescribe a method, but requirement (b), being capable of identifying the signer, is usually met by an identity check before a certificate is issued.
Is a PAdES signature an advanced electronic signature?
Not by itself. PAdES is a format for signatures in PDFs. Whether a PAdES signature is advanced depends on whose key made it and how the signer was identified.
Does Sign PDF provide advanced electronic signatures?
No. Sign PDF provides simple electronic signatures backed by email verification, an audit trail and a sealed, timestamped PDF.
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