Human vs Non-Human Identity: How They Differ and Connect

Every access decision starts with an identity, but not every identity belongs to a person. Identity and access management grew up around employees and customers: people who sign in, answer MFA prompts, change roles and eventually leave. Non-human identities (NHIs), such as service accounts, API keys, OAuth applications, workloads, bots and AI agents, now do much of the work in modern systems, and they behave very differently. This guide compares human and non-human identity side by side, explains why the controls built for people do not transfer cleanly to machines, and focuses on the places where the two meet, because that is where many serious incidents begin.

Key takeaways

Human identities are anchored to a person and governed by HR events. Non-human identities are anchored to software and infrastructure and change with deployments, integrations and code, often with no clear owner.
People authenticate interactively, increasingly with phishing-resistant MFA and passkeys. Machines authenticate by presenting keys, tokens or certificates, or by federating a platform-issued identity. MFA does not apply to them.
The riskiest territory is the overlap: humans using machine credentials, users granting OAuth consent to third-party apps, AI agents acting on a person’s behalf, and help desk or admin accounts that can create or modify NHIs.
AI agents are a hybrid. They act for a person but authenticate as software, so they need delegated, scoped and traceable access rather than a copy of the user’s credentials.
Govern both under one programme with shared principles (inventory, ownership, least privilege, review, revocation), but do not force NHIs through processes designed for users.

What counts as a human identity and a non-human identity

Human identities

A human identity is a digital account that represents a natural person. It typically falls into one of two groups:

Workforce identities: employees, contractors and temporary staff who use internal systems, SaaS applications and cloud consoles. They are usually created from an HR or contractor record and managed through a central identity provider. Administrators are a privileged subset of this group.
Customer and partner identities: people outside the organisation who sign in to its applications or portals. They often register themselves, may link a social or partner login, and are governed by consent, privacy and fraud controls rather than HR events.

The standard reference for how people prove who they are online is NIST SP 800-63-4, Digital Identity Guidelines, which covers identity proofing, authentication and federation. Its scope is explicit: “person” refers only to natural persons, and the guidelines do not directly address machine-to-machine authentication, connected devices or API access on behalf of subjects. The most widely cited digital identity framework was written for people, not machines.

Non-human identities

A non-human identity is any identity used by software rather than a person to authenticate and gain access. Common forms include:

Service accounts: directory, cloud or platform accounts that applications and scripts run as.
API keys and access tokens: strings that grant access to an API, often long-lived and bearer-only.
OAuth applications and integrations: third-party or internal apps granted access to SaaS data, frequently holding refresh tokens.
Workload identities: identities attached to virtual machines, containers, functions and CI/CD jobs, ideally issued by the platform rather than stored as secrets.
Bots and automation: RPA bots, chat bots and scheduled jobs.
AI agents: software that plans and takes actions using tools and APIs, often on behalf of a user.

Platforms often make the split explicit. The Kubernetes authentication documentation, for example, describes two categories of users: service accounts managed by Kubernetes, and normal users, for which Kubernetes has no objects at all because they are managed by an external service. The machine identity lives inside the platform; the human identity lives outside it.

Human vs non-human identity: side-by-side comparison

The table below compares the two across the dimensions that matter most for security and governance. These are generalisations, but the defaults are what attackers exploit.

Dimension	Human identity	Non-human identity
Who creates it	HR or onboarding processes, or the customer through self-registration.	Developers, platform engineers, CI/CD pipelines, infrastructure as code, SaaS admins and, increasingly, end users approving integrations.
Who owns it	The person it represents, with a manager accountable for workforce access.	Often unclear. Ownership must be assigned deliberately to a team or individual, and it degrades when people move on.
How it authenticates	Interactive sign-in with passwords, MFA, passkeys and single sign-on.	API keys, client secrets, tokens, certificates, SSH keys, or platform-issued and federated workload identity.
Lifecycle triggers	Joiner, mover and leaver events from HR or the customer relationship.	Deployments, new integrations, code changes, environment builds and decommissioning.
Volume and change rate	Tracks headcount or customer base; changes at the pace of hiring and role changes.	Grows with every service, pipeline and integration; ephemeral workloads may exist for minutes.
MFA applicability	Expected, and phishing-resistant MFA is the target for privileged users.	Not applicable. Strength comes from removing static secrets, binding credentials and limiting lifetime.
Access review	Periodic certification by managers or application owners against a known role.	Requires usage data and a named owner; reviewers often cannot tell what the identity does without telemetry.
Typical credentials	Password plus authenticator, passkey, smart card, session cookies.	Long-lived keys and secrets, OAuth refresh tokens, short-lived access tokens, X.509 certificates.
Visibility	Usually centralised in an identity provider and HR system.	Scattered across clouds, SaaS tenants, code repositories, vaults and CI/CD systems.
Offboarding	Triggered by the leaver event; disable the account and revoke sessions.	No natural trigger. Credentials must be revoked, rotated or retired when the workload, integration or owner goes away.

Two rows explain most of the risk gap. Human identities have a natural lifecycle signal (the HR record) and a natural second factor (the person). NHIs have neither, which is why the key challenges for NHIs centre on sprawl, ownership and credentials that outlive their purpose.

Authentication: people prove presence, machines prove possession

How humans authenticate

Human authentication is interactive: a person signs in and presents one or more factors. Current guidance pushes strongly towards phishing-resistant methods:

NIST SP 800-63B-4 requires verifiers at AAL2 to offer at least one phishing-resistant option, and requires AAL3 authenticators to be phishing-resistant with a non-exportable private key. Syncable authenticators are not permitted at AAL3.
Passkeys, based on FIDO standards, let a person sign in with the same gesture they use to unlock their device. The FIDO Alliance describes both synced passkeys and device-bound passkeys (including those on security keys).
CISA’s fact sheet on implementing phishing-resistant MFA names FIDO/WebAuthn and PKI-based MFA as the phishing-resistant forms.

Single sign-on and federation then carry that authenticated session to many applications, so the strength of the initial sign-in and the protection of the resulting session tokens matter more than any individual application password.

How non-human identities authenticate

A machine has no fingers, no phone and nobody to approve a push notification. It authenticates by presenting something it holds or something the platform vouches for:

Static secrets: API keys, passwords and client secrets. Whoever holds the secret is the identity.
Tokens: OAuth access and refresh tokens, and signed JWTs. Access tokens are usually bearer tokens unless they are sender-constrained.
Certificates and keys: mutual TLS, signed client assertions and SSH keys, where proof depends on a private key.
Platform-issued and federated identity: cloud roles, managed identities, Kubernetes service account tokens, SPIFFE identities and workload identity federation, where the runtime attests the workload and issues short-lived credentials.

The NHI Authentication Guide covers each method in depth. The core design principle is different from human MFA: since a machine cannot add a second factor, strength comes from removing long-lived secrets, binding tokens to their holder and keeping lifetimes short. The OAuth 2.0 Security Best Current Practice (RFC 9700) recommends sender-constrained access tokens and restricting token privileges to the minimum needed for the use case.

Why “just add MFA” does not work for NHIs

Organisations sometimes apply human controls to machine accounts: enforcing MFA on a service account, or exempting it from conditional access because it cannot satisfy an MFA prompt. The first breaks automation; the second quietly creates an account that bypasses the controls every human account must pass. Neither is a design. The right answer is to move the NHI to an authentication method suited to machines and to constrain where and how it can be used, which is also the direction of NIST SP 800-207 Zero Trust Architecture: no implicit trust based on network location, and protection focused on resources rather than network segments.

Lifecycle and governance: joiner-mover-leaver vs create-rotate-retire

The human lifecycle

Workforce identity governance is built around joiner, mover and leaver events. A new hire record creates accounts and birthright access; a role change should add new access and remove the old; a departure disables accounts and revokes sessions. Provisioning standards such as SCIM (RFC 7644) automate this between identity providers and applications. Periodic access certification then asks managers to confirm that access still fits the role. For a fuller treatment of these foundations, see IAM and IGA Basics.

The non-human lifecycle

NHIs follow a create, use, rotate, review and retire pattern that is driven by engineering activity rather than HR. The NHI Lifecycle Management Guide sets out each stage; in short:

Create: through a controlled request or pipeline, with a purpose, owner, scope and expiry recorded at birth.
Use: from known workloads and locations, with activity logged and attributable.
Rotate: on a schedule and on suspicion of exposure, which is operationally hard when credentials are embedded in many places, as the guide to NHI rotation challenges explains.
Review: against actual usage, not just granted permissions.
Retire: when the workload, integration or project ends, not when someone happens to notice.

The absence of a natural leaver event is why OWASP lists NHI1:2025 Improper Offboarding first in the OWASP Non-Human Identities Top 10 (2025). OWASP specifically calls out NHIs that stay active after the employee responsible for them leaves, and recommends integrating offboarding with HR processes and periodically recertifying NHI ownership.

Ownership is the bridge

The practical link between the two lifecycles is ownership. Every NHI should have a named owning team and an accountable individual, recorded where your inventory lives. When that individual changes role or leaves, the human mover or leaver event should trigger a review of the NHIs they own: reassign, rotate any credentials they could have seen, or retire. This is one of the few places where human lifecycle automation directly strengthens NHI governance, and the lifecycle processes section of the Ultimate Guide treats it as a core control.

Where human and non-human identities meet, and why it is risky

Most identity programmes manage people and machines in separate silos. Attackers do not respect that boundary. The junctions below are where one kind of identity is used to gain the other’s access, and they deserve specific controls.

Humans using NHI credentials

Shared service account passwords in a team vault, a personal access token pasted into a script, an administrator signing in to a console as a service account to save time: all of these mix human behaviour with machine credentials. OWASP names this NHI10:2025 Human Use of NHI, noting that developers often impersonate service accounts to debug issues and that most platforms cannot easily tell a workload using an NHI from a person using it. The consequences are lost accountability, MFA bypass and access broader than the person’s role.

The reverse happens too: machine credentials leak into human spaces such as chat, tickets and personal accounts, feeding secret sprawl. The Okta support system breach involved a service account whose credentials had been stored in an employee’s personal Google account, a clear case of a machine credential crossing into a human’s personal space.

OAuth consent: users creating NHIs without realising it

When a user clicks “Allow” on an OAuth consent screen, they create a durable non-human access path: a third-party application now holds tokens that can read mail, files or CRM data, often long after the user has forgotten about it. Several incidents follow this pattern:

In the Microsoft OAuth breach, phishing led users to consent to malicious applications that then obtained tokens to their Microsoft 365 data without needing passwords.
The CoPhish campaign used Copilot Studio agents to present convincing consent flows and exfiltrate the resulting OAuth tokens.
In the Vercel Context.ai breach, an employee’s OAuth grant to a third-party AI tool became the entry point once that vendor was compromised.
The Salesloft Drift and Klue breaches show what happens when a vendor holding many customers’ OAuth tokens is compromised: one breach reaches many tenants.

Controls sit on both sides. On the human side, restrict who can consent to what. In Microsoft Entra ID, for example, user consent settings can disable user consent or limit it to verified publishers and low-impact permissions, with an admin consent workflow for anything else. On the NHI side, inventory every consented application, review its scopes and last use, and have a revocation runbook ready for when a vendor reports a compromise.

Help desk and admin accounts that create or control NHIs

The people who can create service principals, add credentials to applications, grant consent tenant-wide or mint API keys are, in effect, the controllers of your machine identities. Compromise one of them and the attacker can manufacture persistent non-human access that survives a password reset. The Storm-2949 Azure breach began with social engineering of a human identity through fake IT support calls, after which the attackers enumerated service principals and attempted to add credentials to them. In the Midnight Blizzard breach, a legacy test account without MFA led to OAuth applications with elevated privileges. Treat these administrative capabilities as privileged: require phishing-resistant MFA, limit standing assignment, and alert on new credentials added to existing applications.

Privileged humans vs privileged machines

Privileged access management traditionally focuses on human administrators: vaulting their credentials, brokering sessions, granting just-in-time elevation and recording activity. Privileged machines, such as a CI/CD role that can deploy to production, a backup service account with domain-wide read, or an integration with tenant-wide mail access, often hold equal or greater power with far less oversight. Both need the same questions answered: who or what holds this privilege, why, for how long, and who approved it. The mechanisms differ; session recording and approval prompts suit people, while scoped short-lived credentials and policy-as-code suit machines. The Privileged Access Management Guide covers the human side in detail.

AI agents: acting for a person, authenticating as software

AI agents sit squarely in the overlap. An agent that books meetings, triages tickets or changes infrastructure is acting on a person’s instructions and often with that person’s authority. Yet it runs as software, calls APIs with tokens and can act at machine speed, without a human confirming each step. That makes it neither a user nor a conventional service account.

Delegation, not impersonation

The worst pattern is giving an agent a copy of the user’s credentials or a long-lived personal token. Every action then looks like the user, the agent inherits all of the user’s access, and there is no way to limit or revoke the agent separately. The better pattern is delegation. OAuth 2.0 Token Exchange (RFC 8693) draws exactly this distinction: in impersonation the acting party becomes indistinguishable from the subject, while in delegation it keeps its own identity and acts as an agent for the subject. A delegated token can carry an act (actor) claim that identifies the acting party, and nested actor claims can record a chain of delegation. The request pairs a subject_token (the user on whose behalf the request is made) with an optional actor_token (the agent).

Least privilege for agents

Give each agent its own identity, registered and owned like any other NHI, rather than borrowing a user or a shared service account.
Scope delegated tokens to the task, the target resource and a short lifetime; the agent should never hold more than the user could do, and usually far less.
Keep humans in the loop for high-impact actions, such as deleting data, moving money or changing access. The Replit AI tool incident, in which an agent ran destructive commands against a production database, shows why write access to production needs separate approval.
Log both identities, so every action records the agent that performed it and the user it acted for.

The OpenID Foundation’s whitepaper, Identity Management for Agentic AI, makes a similar point: existing frameworks work reasonably well for agents inside one organisation, but recursive delegation chains and cross-domain trust need further standards work, and enterprises should manage agents as first-class identity subjects with their own lifecycle and governance. For agent-specific threats such as tool misuse and identity abuse, see the guide to the OWASP Top 10 for Agentic Applications.

Governing both under one programme, without treating NHIs as users

Separate silos leave gaps at exactly the junctions described above. But folding NHIs into a user-centric IGA process tends to fail too: certification campaigns ask managers to approve accounts they do not recognise, joiner-mover-leaver logic has nothing to hook onto, and MFA policies either break automation or get exempted. A workable model shares principles and data while keeping mechanisms fit for each identity type.

What to share

One inventory and one risk view. Human and non-human identities, and the links between them (owner, creator, consenting user, delegating user), in a single place.
Common policy principles: least privilege, time-bound access, separation of duties, and evidence of review.
Shared detection: anomalies such as a service account signing in interactively, or a human account using a workload’s credential, only show up when both are monitored together.
Linked lifecycle events: a human leaver or mover event triggers review of the NHIs they own, created or consented to.

What to keep separate

Authentication policy: phishing-resistant MFA for people; keyless, short-lived and bound credentials for machines.
Lifecycle triggers: HR events for people; deployment, integration and decommissioning events for NHIs.
Review method: role-based certification for people; usage-based review by technical owners for NHIs, with unused identities flagged for retirement automatically.
Remediation: disabling a user is quick; revoking a production credential needs coordination and rotation to avoid outages.

Common failure patterns are well documented in the Top 10 NHI issues. For the human side of the programme, the Workforce Identity Security Guide covers sign-in, session and help desk controls.

Practitioner checklist

Build one inventory that covers human accounts and NHIs, including consented OAuth applications and AI agents.
Assign every NHI an owning team and an accountable person; record purpose, scope and expiry at creation.
Link human mover and leaver events to a review of the NHIs that person owns, created or consented to.
Stop humans using NHI credentials: give people their own named accounts for maintenance and debugging, and alert on interactive use of service accounts.
Remove shared service account passwords and personal tokens from scripts; move to workload identity or vaulted, rotated credentials.
Restrict user consent to low-risk permissions from verified publishers, and route everything else through admin review.
Review consented applications by scope and last use; keep a revocation runbook for third-party compromises.
Treat the ability to create service principals, add application credentials or grant tenant-wide consent as privileged access.
Require phishing-resistant MFA for administrators and help desk staff, and harden help desk identity verification.
Give AI agents their own identities and delegated, task-scoped, short-lived tokens; never share a user’s credentials with an agent.
Log both the actor and the subject for delegated actions, and require human approval for destructive operations.
Apply privileged access controls to privileged machines as well as privileged people.

Human vs Non-Human Identity