QES
A QES, a qualified electronic signature, is the only kind of electronic signature that eIDAS gives the same legal effect as a handwritten one, in every member state and regardless of where it was created.
Two things make a signature qualified. It has to be created with a qualified signature creation device, hardware or a certified remote service that keeps the signing key out of everyone’s reach including the provider’s, and it has to be based on a qualified certificate issued by a trust service provider listed as qualified on a national Trusted List. A signature that misses either is still valid evidence as an advanced or simple electronic signature, but a court weighs it rather than being obliged to accept it the way Article 25 of eIDAS obliges it to accept a QES. Because the qualified certificate is checked against a Trusted List published by every member state and cross-checked at EU level, a QES created in one country carries the same legal weight when presented in another, which is the cross-border recognition eIDAS was built to guarantee. Most QES today are created remotely: the signer authenticates to a qualified trust service provider's cloud signing service rather than owning dedicated signing hardware, and the provider triggers the signature on a device it controls under the signer's sole authorisation. The signed document itself typically uses one of the PAdES, XAdES or CAdES formats, which embed the certificate and, where long-term validity matters, a timestamp so the signature can still be verified after the certificate has expired. eIDAS 2.0 puts qualified signing in reach of ordinary users by requiring the EUDI Wallet to let a citizen create a QES free of charge for non-professional use, turning a service previously bought from a trust service provider into a wallet feature. A QES signs a document to bind a person to its content; a QEAA instead attests attributes about a person or organisation. Both come from qualified trust service providers, but they answer different questions and are not interchangeable.
Related terms
Does a QES created in one EU country need to be re-verified to be accepted in another?
No. A QES relies on a qualified certificate checked against the issuing member state's Trusted List, and Trusted Lists themselves are cross-checked at EU level, so a verifier in another member state can confirm the certificate's status without a separate national process. This mutual recognition, guaranteed by Article 25 of eIDAS, is what makes a QES usable across borders without extra legal steps.