Signatures & eIDAS

QES, AES, and SES – the difference explained

What the three signature classes under eIDAS mean and when to use each.

Last updated: March 12, 2026

Simple Electronic Signature (SES)

The simplest form. No identity verification required. Suitable for internal documents or low-risk agreements. Example: client questionnaires, internal office communication. Evidentiary value: low.

Advanced Electronic Signature (AES)

Requires a unique link to the signing person and captures of IP address and timestamp. Suitable for mandate agreements, fee agreements, and most internal law firm processes. Evidentiary value: medium to high.

Qualified Electronic Signature (QES) – coming later

Highest security level under eIDAS. Legally equivalent to a handwritten signature (Art. 25(2) eIDAS). Requires identity verification via video ident or eID. Mandatory for: notarially relevant documents, certain court submissions. VollSign does not offer QES yet – it is planned for a later release.

Which signature class for which document?

AES: mandate agreements, fee agreements, powers of attorney in ongoing mandates. SES: internal communications, simple acknowledgements of receipt. Documents requiring the written form (§ 126 BGB, e.g. sureties, rental and loan agreements) currently need a process outside VollSign until QES is available.