Qualified electronic signature (QES, eIDAS)

The QES is the only electronic signature granted by law the effect of a handwritten signature.

Definition

A qualified electronic signature (QES) is, under the European eIDAS regulation, the top tier of electronic signature. It is defined by two cumulative requirements:

• it is based on a qualified certificate issued by a qualified trust service provider;
• it is created using a qualified signature creation device (QSCD), a certified hardware or software device.

Legal effect

eIDAS grants the QES a legal effect equivalent to a handwritten signature. It is the only signature tier with this automatic equivalence, recognised as such in every EU Member State.

Lower tiers — the simple signature and the advanced (AdES) signature — remain admissible as evidence, but without this presumption of equivalence.

Good to know

In electronic invoicing, a QES is generally not mandatory: most frameworks accept business controls or an advanced signature to ensure integrity and authenticity. A QES is more typically required for high-stakes contracts or specific sectoral obligations.

The XAdES, CAdES and PAdES profiles can reach the qualified level whenever a qualified certificate and a QSCD are used.