Machine identity security is the practice of managing the certificates, keys, tokens and service accounts that let software, devices and workloads prove who they are. It covers discovery, issuing, rotation, expiry and revocation. Most failures come from identities nobody tracks, not from broken cryptography.
What counts as a machine identity?
Anything non-human that authenticates. TLS server certificates, code signing keys, SSH keys, API tokens, cloud service accounts, container workload identities and the credentials AI agents use to call tools. Few teams have counted them. In a company running cloud services they are likely to outnumber employee accounts, so count your own.
A human login is protected by prompts, second factors and a person who notices something odd. A machine credential has none of that. It works silently, wherever it is copied.
What goes wrong?
NIST SP 1800-16, a practice guide on TLS server certificate management, lists the challenges organizations face and describes a certificate management program built to prevent, detect and recover from certificate-related incidents. Two failure modes are easy to see in practice: certificates expire and break a service, and certificates or keys are lost, copied or issued without proper control.
The same pattern shows up with other credentials. An API key pasted into a chat to debug a problem keeps working for years. A service account made for a one-week project holds admin rights forever. A key on a former employee's laptop still opens production.
A constructed example: a company moves a payments service to new infrastructure. A certificate on an old load balancer expires on a Saturday because the person who set it up left a year ago and the reminder went to their mailbox. Checkout is down until Monday. Nothing was attacked. The cause was an identity with no owner and no expiry alert.
How do modern approaches reduce the risk?
Short life is the main lever. The SPIFFE standards describe a framework for securely identifying software systems in dynamic environments, built around short-lived cryptographic identity documents called SVIDs that workloads use to authenticate to each other, for example in a TLS connection or by signing a JWT. SPIFFE's own overview says that network rules based on IP addresses struggle to scale with dynamic environments, and that workloads need a first-class identity.
Short-lived credentials limit the damage of theft. A stolen token that expires in an hour is a smaller problem than a key that never expires. Automated issuing and renewal means nobody has to remember a calendar date.
Where does this meet software supply chain security?
Build systems hold some of your most powerful identities: signing keys, registry tokens and deployment credentials. An attacker who gets one can publish software under your name. Treat pipeline credentials like production credentials: scoped narrowly, short-lived and logged.
AI agents widen the problem. An agent that calls tools needs its own identity with its own limited permissions, rather than borrowing a developer's token. Safeguard offers agent identity as part of its platform, along with policies and guardrails for what agents may do.
How to check or apply this
- Build an inventory: certificates, keys, tokens and service accounts, each with an owner, purpose, location and expiry.
- Scan repositories, build logs and chat exports for exposed secrets, and rotate any you find.
- Put an owner on every identity. If nobody owns it, disable it and see who complains.
- Move to short-lived credentials where your platform supports them, and automate renewal.
- Alert on expiry at 30, 14 and 3 days to a shared mailbox, not a person.
- Give each service and agent its own identity with the least access it needs.
- Test revocation: pick one credential and confirm you can kill it fast.
Quick check
Are API keys machine identities?
Yes. Any credential that lets software authenticate, including keys, tokens, certificates and service accounts, is a machine identity.
Why prefer short-lived credentials?
If one is stolen, it stops working soon. Automated renewal also removes the risk of a forgotten expiry date causing an outage.
Sources
Last reviewed: 18 October 2026.
