eIDAS

eIDAS is the EU regulation that governs electronic signatures, seals, timestamps, and the trust services behind them. Its name stands for electronic IDentification, Authentication and trust Services, and because it is a regulation it applies directly across every EU member state, so the rules for an e-signature are broadly the same whether your counterparty sits in Germany, Spain, or Ireland. Its most important principle for everyday signing is non-discrimination: under Article 25, a signature cannot be denied legal effect or rejected as evidence in court purely for being electronic or for not meeting the requirements of the highest tier.

What makes eIDAS distinctive is that it defines three escalating tiers of e-signature, each with stricter technical requirements and more self-contained proof. A Simple Electronic Signature (SES) is the broadest category: a typed name, a drawn signature, or a clicked I agree box can all qualify. An Advanced Electronic Signature (AES) must be uniquely linked to the signer, able to identify them, created with data under their sole control, and bound to the document so any later change is detectable. A Qualified Electronic Signature (QES) is an AES created with a qualified signature creation device and a qualified certificate from a qualified trust service provider.

Only the QES tier gets special status under eIDAS: it carries the same legal effect as a handwritten signature automatically, and a QES based on a qualified certificate issued in one member state must be recognized as a QES in all the others. For SES and AES, enforceability still depends on the facts, the surrounding evidence, and national law, which is exactly why a strong audit trail matters at the lower tiers. The tier you choose does not decide whether a signature counts; it decides how much extra proof you might need if someone disputes it.

eIDAS is the EU counterpart to the United States ESIGN Act (2000) and UETA (1999), but where the US laws are technology-neutral and define no formal tiers, eIDAS structures assurance into the SES, AES, and QES ladder. For most real-world signing, an SES or AES backed by a detailed, timestamped audit trail is proportionate; the qualified tier is reserved for documents that legally require a handwritten-equivalent signature or carry the highest stakes.

Examples

• A routine SES: a contractor signs a service agreement by drawing their name on a phone, with the audit trail capturing their email, IP, and the time.
• An AES: a vendor contract signed with a private key only the signer controls, so any later edit to the document breaks the signature.
• A QES: a signer uses a qualified certificate and a certified signing device, giving the signature handwritten-equivalent legal effect EU-wide.
• Non-discrimination in practice: an EU court cannot throw out a signed agreement just because the signature was electronic rather than on paper.