clXA

clXA is a cross-domain authentication protocol and framework designed to enable secure single sign-on across heterogeneous organizational systems. The acronym is commonly cited as cross-domain X-authentication. The protocol defines a set of flows and data formats to exchange identity assertions between identity providers and relying parties.

Development and governance: The clXA specification was developed by an international interoperability consortium and published as an open draft in 2019, with a stable 1.0 release in 2020. It is maintained by a community of contributors and hosts discussions on its official repository. There is no formal standards body that endorses clXA, but it has a dedicated testing suite and reference implementations.

Technical overview: clXA relies on JSON Web Tokens and public-key infrastructure to issue and verify identity assertions. It defines a discovery mechanism for trust anchors, allowing relying parties to fetch public keys and metadata from identity providers. The typical flow includes authentication requests, authorization code or token exchange, and subsequent access token issuance. The framework supports mutual TLS, short-lived tokens, and revocation by tokens or status lists.

Usage and reception: In practice, clXA has been adopted by several multinational companies for partner integrations and internal federations. It competes with OAuth 2.0 / OpenID Connect and SAML, and is often layered on top of existing identity platforms.

Security and limitations: Potential risks include misconfiguration, clock drift, token leakage, and revocation gaps. Like other federation protocols, clXA requires careful management of trust anchors, regular key rotation, and robust monitoring.

See also: OAuth 2.0, OpenID Connect, SAML, JWT, Identity federation.