A qualified electronic signature (QES) is an advanced electronic signature created with a qualified electronic signature creation device (QSCD) and based on a qualified certificate issued by a qualified trust service provider. Under eIDAS, a QES has the same legal effect as a handwritten signature throughout the EU.
What makes a signature qualified
Three things must all be true: the certificate is qualified (issued by a provider on an EU trusted list), the signing key is held on a qualified device, and the signature otherwise meets the advanced (AdES) requirements. If any one is missing, the signature is AdES at best, not QES.
How a validator proves QES
A validator confirms QES by checking the signing certificate against the relevant national trusted list and reading the qualification statements there. This is why validation has to resolve the EU List of Trusted Lists, not just verify the cryptography.
Frequently asked questions
What is the difference between AdES and QES?
AdES is uniquely linked to the signer and detects tampering, but is self-asserted. QES adds a qualified certificate and a qualified signing device, which is what gives it automatic legal equivalence to a handwritten signature across the EU.
Validate a QES document free
Send a document to the Sealium API and get back the signature level, signer, certificate chain and timestamps as a structured report. 100 validations a month, free, no card.
Start for free