According to the eIDAS regulations, the qualified electronic signature (QES) is is a digital signature similar to the advanced electronic signature. It provides the highest level of admissibility in the EU courts and has the equivalent legal effect of a handwritten signature.
As with an AES, the qualified trust service provider must verify the identity of the signatory and issue a “qualified certificate” to validate that the signatory is who he claims to be.
The differenece between the AES and the QES is that qualified electronic signatures must be created using a qualified signature creation device (QSCD). This device is responsible for qualifying digital signatures by using specific hardware and software that ensures that the signatory only has control of their private key.