The difference between Advanced and Qualified electronic signatures (AES and QES) under the EU’s eIDAS Regulation
8 January 2025Corporate Clients, Private Clients
Under EU regulations, specifically the eIDAS Regulation (910/2014), electronic signatures are classified into three types: simple electronic signatures, advanced electronic signatures (AES), and qualified electronic signatures (QES). The difference between an advanced electronic signature and a qualified electronic signature lies in the level of security, certification requirements and legal effects.
Advanced Electronic Signatures (AES)
An Advanced Electronic Signature must:
- Uniquely link to the signer.
- Be capable of identifying the signer.
- Be created using creation data that the signer can use under their sole control.
- Linked to the data signed in such a way that subsequent changes are detectable.
These signatures can be generated using various secure technologies but are not required to be certified by a Qualified Trust Service Provider (QTSP).
While they are legally binding, their validity might need to be proven in the courts of EU member states by demonstrating compliance with the above requirements.
Qualified Electronic Signatures (QES)
A qualified electronic signature is a type of advanced electronic signature that meets additional stringent requirements. According to Article 3(12) of eIDAS, it:
- Must be based on a qualified certificate issued by a Qualified Trust Service Provider (QTSP).
- Must be created using a qualified electronic signature creation device (QSCD), such as a secure hardware token or a smart card.
The QES has the highest level of legal assurance and is equivalent to a handwritten signature by law in all EU Member States, as per Article 25(2) of eIDAS. This means it is automatically recognized as a lawfully signed document.
Key Differences
| Feature | Advanced Electronic Signature (AES) | Qualified Electronic Signature (QES) |
| Legal Status | Legally binding but not automatically equivalent to a handwritten signature. | Automatically equivalent to a handwritten signature. |
| Certification | No requirement for a qualified certificate or trust service provider including a QTSP. | Requires a qualified certificate issued by a QTSP. |
| Signature Device | Can be created using any secure method under sole control of the signer. | Must use a qualified signature creation device (QSCD). |
| Trust Level | High level of trust, but validity may need to be demonstrated in court. | Highest level of trust and presumption of legal validity. |
| Cross-Border Recognition | Recognition depends on compliance demonstration. | Automatically recognized across all EU Member States. |
In summary, a QES provides stronger legal assurance and is subject to stricter requirements than an AES, making it the preferred option for transactions requiring the highest level of trust, such as notarized agreements or government filings.