Electronic signatures have become standard practice in today’s increasingly digital European business environment. However, not all digital signatures are created equally.
Many organisations still rely on Advanced Electronic Signatures (AES), missing out on the legal, operational, and cross-border advantages offered by Qualified Electronic Signatures (QES). As organisations continue to digitalise and regulations evolve, however, choosing QES is becoming the clear strategic choice.
In this blog, we explore 6 compelling reasons why organisations should adopt QES instead of AES, from legal certainty and regulatory trends to cost efficiency, security, convenience, and ease of integration.
QES is issued only after strict identity verification of the signer, and the cryptographic identification proof is embedded directly in the signed document. As a result, QES is the only type of electronic signature that automatically carries the same legal effect as a handwritten signature across all EU member states.
In contrast, AES meets a lower validation threshold, because its legal strength depends entirely on the system and controlled environment in which it is created.
“With AES, the relying party controls the signing environment and must be able to prove the signature’s validity within their own system,” explains itsme®’s CISO Olaf Jonkers. “Reproducing that evidence in court can be more challenging, often requiring additional logs or expert analysis. Traceability is also more limited.”
The difference in legal certainty between AES and QES directly affects how efficiently organisations can prove agreements, resolve disputes, and demonstrate compliance across the EU.
"AES is about identifying the signer, which is essentially equivalent to authentication or login, not a signature per se," explains Lise Plaziat, Partnership Manager at itsme®. “Because it does not include a dedicated certificate like a QES, its legal validity is limited to specific contexts.”
QES on the other hand eliminates uncertainty. The qualified trust service provider (such as itsme®) carries the responsibility for proving the signer’s identity in court and provides the highest legal assurance, making QES not just a compliance tool, but a business enabler.
For first-time signers, QES creates an identity-backed certificate issued by a qualified trust service provider, offering a level of assurance comparable to presenting a passport. Documents signed with QES can be verified through the EU’s official signature validation tool, which confirms whether the signature is qualified and legally valid under eIDAS.
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While AES remains acceptable for many agreements, regulatory trends such as eIDAS 2.0 are steadily accelerating the shift toward QES, making it the preferred (and in some cases the only legally compliant) option for high value, cross border or legally sensitive contracts.
Across the EU, member states are adapting accordingly. In Belgium, for example, digitally signed employment contracts must use QES (or the qualified certificate on the Belgian eID). Notarial deeds, authentic acts, and other documents overseen by public authorities also require QES. Regulated sectors, including banking, finance, and insurance, increasingly rely on QES for customer onboarding, high-value agreements, and AML/KYC compliance processes.
According to itsme®'s data, QES adoption in Belgium is growing year on year, driven by rising awareness of its legal importance and user-friendly design. Since 2025, the Flemish government has implemented QES via itsme® across its various sectors, including schools, the police, and city halls. This has significantly increased awareness of QES as a signing option across Flanders.
While some companies may wait until the last minute to adopt QES, doing so risks creating compliance gaps. As new technical standards from eIDAS 2024–2026 take effect, AES-based agreements may no longer provide sufficient legal certainty in regulated sectors.
"It is only a matter of time before QES becomes the standard across the EU," advises Lise. "Adopting the highest level of security from the start ensures legal certainty and trust for companies."
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For high-stakes contracts, such as loans, insurance policies, employment agreements, or notarial acts, organisations that rely on AES often fall back on manual processes, including handwritten signatures, couriered documents, or branch visits. These fallbacks hinder the goal of fully digital operations and disrupt the user experience.
By providing maximum legal certainty under eIDAS 2.0, QES enables fully digital processes in real-world applications, even for critical, high-risk operations. This includes, for instance:
Cross-border validity is another key advantage. A signature issued in Belgium, for example, is automatically valid in all EU member states under eIDAS High Assurance, eliminating delays from local validation, re-signing, or in-person checks.
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A common misconception is that QES is more expensive than AES. In reality, when factoring in all the components required for trust, compliance, and cross-border acceptance, the total cost of ownership often makes QES the more economical choice.
On the one hand, both AES and QES produce self-contained documents that cannot be altered. Because the proof of authenticity is embedded in the document, no additional verification is needed. On the other hand, AES can carry hidden costs, since its legal reliability depends on maintaining a controlled environment for tasks such as certificate management, secure storage, and ongoing operational oversight.
“Even if you get AES certificates from a third party, you still need to account for setup, usability, and ongoing operational overhead,” Olaf explains. “When you include certificate management, storage, and the total cost of ownership, AES is rarely significantly cheaper than QES.”
By contrast, QES embeds trust directly in the signature and the document, eliminating reliance on external infrastructure or complex organisational processes. Every document signed by QES becomes standalone evidence, recognised across all EU member states without question.
"With QES, everything is all-inclusive: this includes the trust, the certificate, and the cross-border legal recognition” adds Olaf. "For any contract or document that needs to be preserved long term and carries important legal guarantees, I would not hesitate to choose QES."
For EU-wide operations, QES delivers significant cost advantages through its cross-border validity. This is because an AES-signed document from one country may require manual verification in another, while a QES is automatically recognised in all 27 member states.
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Depending on the provider, QES can offer a far more convenient user experience than AES. Traditional AES solutions often rely on one-time passwords (OTP) sent via SMS or other cumbersome methods, creating friction for users and increasing operational costs.
In contrast, QES, especially when integrated with platforms like itsme®, removes these obstacles. Because itsme® is a mobile app that millions of users already use in their daily lives, the signature tool resides in the smartphone, always within reach, without the hassle of old methods like USB sticks containing private keys.
itsme®’s QES solution also accepts national IDs from 30 countries in Europe, enabling smooth onboarding and signing for a wide range of users.
Additionally, managing QES certificates with a partner like itsme® is very straightforward, as itsme® can revoke or reissue them at any time, and all a user has to do is confirm the new certificate.
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Implementing QES is simpler than many companies assume. Modern signature platforms such as Nitro, Penneo, Dioss, and others already integrate QES via qualified trust service providers like itsme®, providing ready-to-use solutions compatible with existing workflows.
Most companies can adopt QES without overhauling their current AES infrastructure. For instance, existing document management or contract automation systems can often be configured to swap AES with QES signatures with minimal technical effort. The platforms handle certificate management, cryptographic proof, and EU-wide legal recognition, allowing companies to focus on operational adoption rather than backend complexity.
This accessibility lowers barriers to entry, making QES a practical option even for mid-sized businesses or organisations with established AES processes.
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