Level of Assurance
Level of assurance, often shortened to LoA, is how much confidence a relying party can place in a claimed identity. eIDAS defines three: low, substantial and high.
The level is set by two things: how thoroughly the person was identified when the credential was first issued, and how well the credential is protected and bound to them afterwards. Low covers a self-asserted registration with little verification; substantial requires evidence that the identity is genuine and a login that uses more than one factor; high additionally requires that the identity was checked against an authoritative source, in person or by an equivalent remote procedure, and that the credential sits in tamper-resistant hardware. It matters because it decides what a credential may be used for: member states must recognise notified schemes at substantial or high for access to public services across borders, and the EUDI Wallet is required to be issued at high. A verifier therefore asks for the level its own risk requires rather than accepting any identity at all.