Authentication (AuthN) verifies "who you are" - confirming the identity of a user, system, or entity. Authorization (AuthZ) determines "what you can do" - deciding what resources or actions an authenticated entity is permitted to access.
Key differences:
Authentication happens first and establishes identity
Authorization happens after authentication and grants permissions
Authentication is binary (you are or aren't who you claim to be)
Authorization is granular (different levels of access to different resources)
Real-world analogy: Think of entering a secure building:
Authentication: Showing your ID badge at the entrance to prove your identity
Authorization: The badge determines which floors, rooms, and systems you can access
Rewriting in plainer words…
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