What is the difference between a non-human identity and a machine identity?
By Identra · Updated
In the taxonomy Identra uses, non-human identity (NHI) is the broader umbrella term, while a machine identity is an infrastructure identity for devices and workloads, authenticated with credentials such as TLS certificates, SSH keys, and secrets. NHI adds SaaS-native actors such as service accounts and OAuth apps, plus AI agents, each presenting its own tokens and keys. Every machine identity is an NHI; the reverse is not true.
Key numbers
- Machine identities outnumber human identities 82 to 1 in the average organization (CyberArk Identity Security Landscape, 2025)
- Organizations average roughly 20 non-human identities per human identity, a lower figure that reflects a narrower survey definition (Enterprise Strategy Group, 2024)
- 23.8 million secrets, the credentials behind non-human identities, leaked on public GitHub in 2024 (GitGuardian State of Secrets Sprawl, 2025)
Why are the two terms confused?
The terms come from two different eras of security. Machine identity is the older label, rooted in PKI and certificate lifecycle management. The vendors who built that category spent a decade managing X.509 certificates, SSH keys, and device identities for networks and data centers, so the word machine still carries an infrastructure accent.
Non-human identity is the newer label, coined by cloud and SaaS security practitioners around 2023 to name a population the certificate world never covered: OAuth grants, service accounts, API keys, and automation tokens living inside SaaS platforms and cloud consoles. Some vendors now use the terms interchangeably, others invert the hierarchy, which is why search results contradict each other.
The definitional spread even shows up in the headline numbers. CyberArk's 2025 Identity Security Landscape counts the whole population as machine identities and reports an 82 to 1 ratio against humans, while Enterprise Strategy Group's 2024 survey counts non-human identities and lands near 20 to 1. The gap is partly growth and partly scope: the wider you draw the circle, the bigger the ratio.
What is a machine identity?
A machine identity authenticates a piece of infrastructure, physical or virtual, usually with a cryptographic credential. The discipline around it, machine identity management, grew out of stopping certificate expiry outages and untracked SSH keys, and its lifecycle verbs are issue, rotate, and revoke.
- TLS/SSL and X.509 certificates that authenticate servers and services
- SSH keys granting access between hosts
- Device identities for laptops, servers, IoT, and network gear
- Workload identities for containers, VMs, and microservices, including SPIFFE/SPIRE-style attestations
What is a non-human identity?
A non-human identity is any authenticated actor that is not a person. That includes everything above, plus the SaaS-native and application-layer actors that certificate tooling never saw: identities created in an admin console or a line of code rather than issued by a certificate authority. Their lifecycle verbs are different too: provision, scope, monitor, and deprovision.
- Service accounts in cloud platforms, databases, and directories
- OAuth apps and the standing grants users approve for them
- API keys, personal access tokens, and webhook secrets
- CI/CD pipelines and automation bots acting with stored credentials
- AI agents and the tool-calling identities they operate through
Machine identity vs. NHI at a glance
The cleanest way to hold the two terms, and the way Identra draws the line: machine identity is a subset of non-human identity, anchored in infrastructure and cryptographic credentials. NHI is the umbrella, anchored in the question of who is acting, regardless of where the credential came from. Vendors draw this boundary differently, so treat it as one workable taxonomy rather than a settled standard.
| Dimension | Machine identity | Non-human identity (NHI) |
|---|---|---|
| Origin | PKI and certificate management, 2010s | Cloud and SaaS security, circa 2023 |
| Anchor | Cryptographic credential bound to a device or workload | Any authenticated actor that is not a person |
| Typical examples | TLS certificates, SSH keys, device and workload identities | Service accounts, OAuth apps, API tokens, bots, AI agents |
| Lifecycle verbs | Issue, rotate, revoke | Provision, scope, monitor, deprovision |
| Home turf | Networks, data centers, cloud workloads | SaaS platforms, cloud consoles, code, pipelines |
| Relationship | Subset | Umbrella term |
Is a service account a machine identity or an NHI?
Both, and it is the clearest example of why the taxonomy matters. A cloud service account authenticates a workload, which is the machine identity view, and it also persists as a standing privileged actor with entitlements, an owner (often unknown), and long-lived keys, which is the NHI view.
The label you reach for changes the controls you apply. Call it a machine identity and you think about key rotation and certificate hygiene. Call it an NHI and you think about ownership, least privilege, entitlement review, and monitoring what it actually does. A mature program does both.
Where do AI agents fit?
AI agents are non-human identities, and they are the reason NHI is winning as the umbrella term. An agent is not a device and rarely holds a certificate, so the machine identity vocabulary fits it poorly. It authenticates with borrowed credentials, acts with delegated human intent, chains API tokens and OAuth grants across tools and MCP servers, and can spawn sub-agents that inherit its access.
Industry frameworks have followed the broader term: the OWASP Non-Human Identities Top 10, published in 2025, catalogs risks like secret leakage, overprivileged NHIs, and long-lived secrets under the NHI banner, with agents squarely in scope.
How Identra thinks about it
The taxonomy debate, to us, is a symptom, not the disease. Both vocabularies were built around provisioning-time control: issue the certificate, create the service account, approve the OAuth grant. But whether you call the actor a machine identity or an NHI, the questions that decide an incident are runtime questions: which non-human actor used which credential, to do what, on whose behalf, and was that normal. An inventory that cannot answer those questions is a census, not a security control, and the arrival of AI agents that acquire and chain credentials mid-task makes the runtime gap the one worth closing first.
Go deeper: The Non-Human Majority
Frequently asked questions
Is machine identity the same as non-human identity?
Not in the taxonomy Identra uses. Machine identity is the older, narrower term for infrastructure identities anchored in certificates, SSH keys, and workload attestations. Non-human identity is the umbrella term that includes all of those plus SaaS-native actors like service accounts, OAuth apps, bots, and AI agents, along with the API tokens those actors present. Every machine identity is a non-human identity, but not the reverse.
Is a service account a machine identity or an NHI?
Both. Viewed as a machine identity, a service account authenticates a workload and needs key rotation and credential hygiene. Viewed as an NHI, it is a standing privileged actor that needs an owner, least-privilege scoping, entitlement reviews, and monitoring. Mature programs apply both sets of controls rather than picking one label and one toolset.
Why do NHI-to-human ratio numbers vary so much between studies?
Because each study draws the category boundary differently. CyberArk's 2025 report counts the whole non-human population as machine identities and reports 82 to 1, while Enterprise Strategy Group's 2024 survey used a narrower non-human identity definition and landed near 20 to 1. The gap reflects scope and survey methodology as much as real growth.
Are AI agents machine identities?
They fit poorly under the machine identity label. An AI agent is not a device, rarely holds a certificate, and authenticates with borrowed credentials like OAuth grants and API tokens while acting on delegated human intent. That is why the industry, including the OWASP Non-Human Identities Top 10, classifies agents under the broader non-human identity umbrella.