What is eIDAS?
eIDAS is the EU regulation on electronic identification and trust services for electronic transactions in the internal market; it defines identity assurance levels and terms such as "reliable source" and "authentic source".
The name expands to electronic IDentification, Authentication and trust Services. It is a regulation of the European Parliament and Council, so it applies directly in EU member states. Two versions matter in IAM discussions: the original framework (with implementing regulation 2015/1502 on assurance levels) and the 2024 revision (2024/1183, "eIDAS 2.0"), which introduces the European Digital Identity Wallet and the "authentic source" concept. Switzerland is not bound by it, but the Swiss E-ID law deliberately aligns its security levels and vocabulary with eIDAS so that the systems can interoperate.
Go deeper:
eIDAS (Wikipedia) — overview of the regulation, its trust services and the 2024 revision with the EU Digital Identity Wallet.- Regulation (EU) 2024/1183 (EUR-Lex) — the eIDAS 2.0 text itself, where authentic sources and the wallet are written into law.