Identity and Access Management (IAM) is the security discipline that ensures the right individuals access the right resources at the right time for the right reasons. It sits at the intersection of cybersecurity, directory services, authentication protocols, and compliance frameworks, functioning as the gatekeeper between users, applications, and sensitive data. Unlike perimeter-based security models that trust everything inside a network, modern IAM operates on continuous verification, dynamic policy enforcement, and fine-grained access control. The key mental model: identity is the new perimeter—every access decision depends on proving who (or what) is requesting access, what they're allowed to do, and whether the context justifies the request.
What This Cheat Sheet Covers
This topic spans 18 focused tables and 122 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.
Table 1: Core IAM Concepts
Before any protocol or product makes sense, you need the vocabulary that everything else builds on—the difference between proving who you are (authentication) and what you're allowed to do (authorization), and the players involved when an identity provider vouches for a user to a service provider. These are the building blocks every later table assembles into real systems.
| Concept | Example | Description |
|---|---|---|
user_id: john.doe | • Digital representation of a person, service, or device within a system • serves as the anchor for all access decisions. | |
User enters password → system verifies | • Process of proving an identity is legitimate • answers "Are you who you claim to be?" through credentials, tokens, or biometrics | |
User has "read" permission on file | • Process of determining what an authenticated identity can access • defines permissions, roles, and policies after identity is proven | |
Okta, Azure AD, Google | • Centralized service that authenticates users and issues tokens • acts as the source of truth for identity verification in federated systems | |
SaaS app that relies on IdP | • Application or service that delegates authentication to an IdP • trusts identity assertions from the provider to grant access |