Advanced Electronic Signature in Public Procurement Law

Definition: The advanced electronic signature is a form of electronic signature which, pursuant to Art. 3(11) and Art. 26 of the eIDAS Regulation (EU) No. 910/2014, is uniquely linked to the signatory, capable of identifying the signatory, created using data under the sole control of the signatory, and connected to the signed data in such a way that any subsequent alteration of the data is detectable.

Last updated: January 2026 · Legal basis: eIDAS Regulation (EU) No. 910/2014, Art. 3(11), Art. 26; Directive 2014/24/EU; BVergG 2018; VgV

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What is an advanced electronic signature?

The advanced electronic signature (AdES) is the intermediate security level in the eIDAS Regulation's tiered system and offers significantly higher security guarantees than the simple electronic signature, but lesser legal effect than the qualified electronic signature.

Art. 26 of the eIDAS Regulation sets out four cumulative requirements that an advanced electronic signature must satisfy:

1. Unique attribution: The signature is uniquely linked to the signatory, so that confusion with other persons is excluded.
2. Identifiability: The signature enables identification of the signatory; the specific mechanism is not prescribed, but it must be reliable.
3. Sole control: The signature is created using signature-creation data which the signatory can, with a high level of confidence, use under their sole control – typically a private cryptographic key.
4. Integrity evidence: The signature is linked to the signed data in such a way that any subsequent alteration of the data is detectable. Any manipulation of the document invalidates the signature.

Technically, AdES is generally based on asymmetric cryptography (public-key infrastructure). The signatory uses a private key to create the signature; verification is carried out using the corresponding public key. A certificate from an accredited trust service provider is not mandatorily required for AdES – it may also be based on non-qualified certificates.

Significance and function

The advanced electronic signature occupies an intermediate position in procurement law: it is more secure than a simple signature, but does not require a qualified certificate and is therefore technically easier to deploy than the qualified electronic signature.

In the procurement-law context, AdES is used in particular for:

• Correspondence in ongoing procurement procedures where reliable attribution to the sender is required,
• Evidence and declarations where no statutory written-form requirement applies,
• Electronic submission of offers via procurement platforms, provided the platform accepts this form of signature.

AdES is not legally equivalent to a handwritten signature: Art. 25(2) eIDAS expressly provides the legal effect of a handwritten signature only for the qualified electronic signature. For documents subject to the statutory written form, AdES is therefore generally not sufficient.

When setting signature requirements, contracting authorities must observe the principle of proportionality. Requiring a QES for simple declarations may be considered a disproportionate barrier for bidders.

Legal basis

The requirements for the advanced electronic signature are exhaustively set out in Art. 26 of the eIDAS Regulation, which, as an EU regulation, applies directly in all Member States.

• EU: eIDAS Regulation (EU) No. 910/2014, Art. 3(11), Art. 26
• Austria: E-Government Act (E-GovG); BVergG 2018 (rules on electronic communication); RTR-GmbH as the competent supervisory authority for trust service providers
• Germany: VgV § 11; Federal Network Agency as supervisory authority; the former German Signature Act has been replaced by the directly applicable eIDAS Regulation

Related terms

• Electronic signature
• Qualified electronic signature
• Electronic procurement
• Offer
• Offer review
• Procurement procedure
• Principle of equal treatment
• Review procedure

FAQ

What is the difference between an advanced and a qualified electronic signature? The essential difference lies in the certificate and the creation unit: the qualified electronic signature mandatorily requires a qualified certificate from an authorised trust service provider and a qualified signature-creation unit (e.g. chip card). The advanced signature is technically less strictly defined and can be created without a qualified certificate. Legally, only the QES has the effect of a handwritten signature.

Can an advanced electronic signature be used for offers in the procurement procedure? This depends on the specific requirements of the contracting authority and the applicable law. For form-bound declarations or contract signatures requiring the statutory written form, AdES is generally not sufficient. Contracting authorities must communicate the relevant requirements transparently in the procurement documents.

Is a certificate required for an advanced electronic signature? The eIDAS Regulation does not require a certificate for AdES. In practice, however, a (non-qualified) certificate is often used, which enables identification of the signatory. The technical details may vary, provided the four requirements of Art. 26 eIDAS are met.

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Last updated: January 2026 All information without warranty. For legally binding advice, please consult a law firm specialising in public procurement law.