-User Authentication(message authentication과는 조금 다르다) ❖ Fundamental security building block basis of access control & user accountability ❖ The process of verifying an identity claimed by or for a system entity(신원검증) ❖ Two steps: Identification: specify identifier(누구냐고 묻는것) Verification: bind entity (person) and identifier(실제로 말한 주체인지 확인하는 것) ❖ Distinct from message authentication integrity of t..