delegationauthorization

Delegation authorization is a mechanism in access control that allows one entity (the delegator) to grant another entity (the delegatee) permission to act on the delegator’s behalf within defined boundaries. It enables services or users to perform tasks or access resources without sharing credentials, while maintaining accountability through traceable tokens, scopes, and time limits.

In practice, delegation can take two forms. Impersonation, where the delegatee operates using the delegator’s identity, and on-behalf-of (OBO) delegation, where the delegatee presents its own credentials together with evidence of the delegator’s rights. Modern systems implement delegation with tokens that encode authorization scopes, lifetimes, and constraints, along with revocation and auditing capabilities.

Common frameworks and patterns for delegation include OAuth 2.0 and OpenID Connect for service-to-service and user-centric delegation, SAML for enterprise single sign-on, and Kerberos constrained delegation in on-premises environments. Access control models such as RBAC (role-based) and ABAC (attribute-based) can be used to define who may delegate, to whom, and under what conditions. Some deployments implement specialized flows, such as OAuth 2.0 on-behalf-of, to obtain tokens representing the original user or delegator.

Security and governance considerations are central. Practices include enforcing least privilege, using short-lived tokens, explicit scopes, robust revocation, comprehensive auditing, and clear ownership. Delegation can introduce risks such as privilege escalation or token leakage if misconfigured, so careful policy definitions and lifecycle management are essential.

See also: OAuth 2.0, OpenID Connect, SAML, Kerberos, RBAC, ABAC.