Identity federation lets a user authenticate once with an identity provider and then access multiple trusted systems across domains. Identity delegation lets a user or system grant another application limited authority to act on its behalf, usually through OAuth 2.0. Federation solves access across systems. Delegation solves scoped action without exposing credentials.
Identity federation and identity delegation solve different problems
Federation is about trust between identity systems, while delegation is about limiting what one actor can do on behalf of another. In practice, federation answers, “Can this person or workload log in here using a trusted external identity?” Delegation answers, “Can this app act for me within a constrained scope without giving it my full credentials?”
The operational difference matters because the security boundary is different. Federation transfers authentication trust across organisations or domains, usually through an identity provider and a relying party. Delegation transfers authority, not identity proof, and the delegated action is typically narrowed by consent, scope, or policy so the recipient can perform a task without becoming the original actor.
How the trust model changes the control you need
With federation, the core control question is whether the receiving system trusts the assertion issued by the external identity provider. That means the important checks are issuer trust, token validation, audience restrictions, session handling, and whether the relying party accepts the asserted identity for access decisions. A good federation design reduces password sprawl and centralises authentication, but it also creates dependency on the federation path.
With delegation, the core control question is whether the granted authority is appropriately bounded. The delegated party should receive only the minimum scope needed, for the shortest practical duration, with clear revocation paths. This is why delegation is often implemented with OAuth 2.0 style consent and scoped tokens: the token is not a blank cheque, it is a constrained capability tied to a specific action set.
- Federation changes authentication trust across systems.
- Delegation changes authorisation boundaries for an application or service acting on behalf of someone else.
- Federation is primarily a login and trust problem, while delegation is primarily a scoped-access problem.
In identity-heavy environments, this distinction becomes more visible when non-human actors are involved. Federation can establish how a service, workload, or external user is recognised by a platform, while delegation determines what the calling application may do once that trust exists. For NHI programs, that separation is important because authentication trust and action authority are often treated as one control when they should not be.
Where teams get it wrong in real implementations
The most common mistake is assuming a federated login automatically means the caller should be able to act broadly. It should not. A valid federated identity only proves who authenticated through the trusted path; it does not justify unrestricted access or downstream impersonation. The second mistake is treating delegation like federation, where broad consent or long-lived tokens quietly expand the blast radius of a compromise.
For practitioners, the practical risk is token misuse, over-broad consent, and confused-deputy behaviour. If the delegated component can call high-value APIs, its scope and audience must be explicit, and the receiving service must verify that the token is intended for that exact use. If the federation trust chain is weak, the issue is different: the environment may accept identities it should not trust at all.
The distinction also affects troubleshooting. A federation failure usually looks like an authentication, trust, or assertion problem. A delegation failure usually looks like an authorisation, consent, scope, or token propagation problem. Mixing them up slows incident triage and leads teams to fix the wrong layer.
Risk and Threat Considerations
Federation and delegation both reduce friction, but they also create high-value trust paths that attackers target. If federation is misconfigured, an attacker may be able to impersonate a trusted identity provider or abuse a weak assertion path. If delegation is too broad, a stolen or over-permissioned token can let an attacker act within a trusted session without needing the original credentials.
Failure mechanism: Federation failures concentrate risk in the trust relationship between identity systems, while delegation failures concentrate risk in scope, consent, and token lifetime. In both cases, a single weak control can expand access across many downstream services. NHI Mgmt Group’s Ultimate Guide to NHIs notes that 97% of NHIs carry excessive privileges, which shows how quickly access can become broader than intended when authority is not tightly bounded.
Impact: The result can be cross-system compromise, data exposure, lateral movement, or unauthorised API action. A delegated token with excessive scope may be enough to damage production systems even when the original credential remains untouched, while a compromised federation trust path can let an attacker enter as an apparently legitimate user or workload.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 address the attack and risk surface, while NIST SP 800-63, NIST CSF 2.0 and CIS Controls v8 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-63 | Federation and Authentication Assurance — Federation and Authentication Assurance | Federation depends on trusted assertions and authentication assurance across domains. |
| Recommendation — Validate federation assertions and assurance level before accepting external identities. | ||
| OWASP Non-Human Identity Top 10 | NHI-01 — Identity and Access Governance | Federated and delegated access can over-expand non-human authority if not governed tightly. |
| NHI-03 — Secrets and Credential Management | Delegated and federated flows rely on tokens and credentials that must be tightly bounded. | |
| Recommendation — Apply least privilege and revoke unused delegated or federated access paths quickly. Restrict token scope and lifetime, and rotate or revoke compromised credential material promptly. | ||
| NIST CSF 2.0 | PR.AA — Identity Management, Authentication, and Access Control | The topic contrasts authentication trust with delegated access authority. |
| Recommendation — Separate identity assurance from authorisation decisions and enforce both explicitly. | ||
| CIS Controls v8 | 6 — Access Control Management | Federation and delegation both require precise access boundaries and revocation. |
| Recommendation — Limit access by role and scope, then remove excess permissions and stale grants. | ||
Practitioner Guidance
What to verify: Confirm whether the design question is about trusted sign-in or scoped on-behalf-of action before choosing a protocol. If the requirement is “let this external identity access our systems,” federation is the better fit; if the requirement is “let this app call this API for this user,” delegation is the right control pattern.
Common mistake: Do not let a successful federated authentication flow become an implicit authorisation grant. The safer implementation is to separate identity proof, consent, scope, and action approval so that each layer can fail closed on its own.
Practitioner takeaway: Federation establishes who is trusted to enter, delegation establishes what a trusted actor is allowed to do, and mature designs keep those decisions deliberately separate.
Related resources from NHI Mgmt Group
- What is the difference between secret rotation and identity federation?
- What is the difference between secret rotation and workload identity federation?
- What is the difference between workload federation and workload identity management?
- What is the difference between SSO and workload identity federation?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 17, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
