An advanced electronic signature (advanced electronic signature or AdES) is an electronic signature that has met the requirements set out in the EU Regulation "Regulation (European Union Law)") No 910/2014 (eIDAS Regulation) on electronic identification and trust services for electronic transactions in the European single market.[1]​.

The eIDAS created standards for the use of the electronic signature, so that it could be used securely when conducting online business, such as an electronic transfer of funds or cross-border official business with EU Member States.[2]​ Advanced electronic signature is one of the standards provided for in the eIDAS.

For an electronic signature to be considered advanced, it must meet several requirements:[3][4]​.

Advanced electronic signatures that comply with eIDAS can be technically implemented through the Ades Basic Profiles that have been developed by the European Telecommunications Standards Institute (ETSI):[3]​.

The implementation of advanced electronic signature under the eIDAS specification serves several purposes. The processes of companies and public services, even cross-border ones, can be streamlined securely through the use of electronic signatures. With eIDAS, EU States must establish "single windows" (PSCs) for trusted services to ensure that electronic identification systems can be used in public sector transactions carried out cross-border, including access to health information across borders.[3]​.

In the past, when a document or message was signed, the signer would sign it and then return it to its recipient through the postal service, by fax service, or by scanning it and attaching it to an email. This could lead to delays and of course the possibility of forged signatures and altered documents, especially when multiple signatures are required from different people located in different locations. The process of using an advanced electronic signature saves time, is legally binding and guarantees a high level of technical security.[3][7]​.