certbat

Certbat is a term used in cybersecurity and software engineering to refer to a compact authentication artifact derived from a digital certificate. It is designed to provide a lighter-weight method of proving a client's identity to a service than presenting a full certificate in every handshake, while offering similar trust guarantees through cryptographic signing.

Origin and usage: The term certbat is not fixed to a single standard; in practice it denotes either an opaque token bearing a certificate thumbprint and a validity window, or a structured token akin to a JSON Web Token that is signed by a trusted authority. In mutual TLS deployments, certbats may be issued by an identity provider and exchanged during API calls or service-to-service authentication, enabling authorization decisions without requiring re-transport of a full certificate.

Composition and validation: A certbat typically contains a subset of certificate-derived claims such as the subject identity, issuer, expiration, and a cryptographic signature. Depending on implementation, it may also encode scope or audience information. Validation involves verifying the signature against the issuer's public key and checking the embedded validity period and revocation status.

Security and considerations: Use-cases favor short lifetimes, strict revocation checks, and careful key management. If a certbat is leaked, its limited scope and expiration mitigate risk compared with a full certificate. Deployment should align with existing PKI policies and access control models.

See also: certificate-based authentication, JSON Web Token, mutual TLS, API gateway, service mesh.