What do the eIDAS regulation 910/2014 and implementing regulation 2015/1502 define for authentication quality, and why do they matter for Switzerland?

They define three assurance levels (low, substantial, high) for notified electronic identification means, so that EU member states can recognise each other's eIDs in a cross-border federation; they do not bind Switzerland, but they are fundamental for any Swiss E-ID to be accepted in the EU.

• Regulation (EU) No 910/2014 (eIDAS) sets the legal framework for electronic identification and trust services in the EU single market.
• Implementing Regulation (EU) 2015/1502 spells out the technical specifications and procedures behind the three levels. Its annex is structured like a quality model: enrolment (application, identity proofing and verification of natural and legal persons), management of the eID means (its characteristics, issuance and activation, suspension and renewal), authentication, and management and organisation (information security management, staff, compliance and audit).
• Goal: a cross-border, federated identity system between the member states. A Spanish service can accept a German eID because both are notified at a known level.
• Switzerland: not an EU member, so not bound. But if Swiss E-IDs are ever to be accepted by EU services, their quality must be expressible in eIDAS terms, which is why the Swiss eCH-0170 model was designed with eIDAS as one of its bases.
• 2024 amendment: Regulation (EU) 2024/1183 ("eIDAS 2") fundamentally revised the framework and introduced the European Digital Identity Wallet that member states must offer to citizens.

Go deeper:

• EU eID: eIDAS Levels of Assurance — the three levels explained with concrete enrolment and authentication examples.
• eIDAS (Wikipedia) — history of the regulation, the 2024/1183 amendment and the EU Digital Identity Wallet.