The identity and authorization layer is the part of a system that proves who a user is and decides what that user is allowed to do. Identity checks usually involve login, tokens, session cookies, or single sign-on. Authorization then applies rules such as roles, permissions, and resource ownership.
This layer is critical because it protects the rest of the environment. If attackers bypass authentication, they can impersonate legitimate users. If they abuse authorization flaws, they may read private data, change settings, or trigger administrative actions they should never reach. In developer platforms and CI/CD tools, weak identity controls can expose code, build pipelines, and connected services.
Defenders harden this layer with strong password policy, multi-factor authentication, least-privilege access, centralized logging, and careful session handling. Regular review of permissions and trust boundaries helps prevent small mistakes from becoming full account compromise.