What is an assurance level (Vertrauensstufe)?

The assurance level states with what quality a subject was authenticated, distinguishing natural and legal persons; the eCH-0170 model derives the overall level from four sub-models: the assurance levels of authentication, registration, governance and federation.

Synonym: Vertrauensniveau. It is the number a relying party looks at to decide whether an assertion is good enough for a given transaction.

Go deeper:

• NIST SP 800-63-4 Digital Identity Guidelines — the identity, authentication and federation assurance levels (IAL, AAL, FAL).
• Implementing Regulation (EU) 2015/1502 (EUR-Lex) — defines the authoritative source and the assurance levels low, substantial and high.