NutFeder

NutFeder is an open standard and software ecosystem for federated identity and access management. It defines a decentralized framework to establish cross-domain trust, issue verifiable attestations, and enable single sign-on among participating organizations. Attestations are cryptographically signed tokens (Nut attestations) carrying minimal attributes and revocation.

NutFeder uses NutRefs, decentralized registries storing domain metadata, trust relations, and consent policies. Validators sign attestations; relying parties verify tokens to grant access. Privacy-preserving features include selective disclosure and revocation lists.

The protocol interoperates with OAuth 2.0, OpenID Connect, and SAML through adapters while maintaining its own trust model. JSON-based messages support cross-domain verification and offline validation.

The project began in the early 2020s via collaboration of researchers and open-source developers; a public specification was released in 2022, with a reference implementation and client libraries in multiple languages. Pilot deployments have occurred in education and non-profit networks.

Governance is handled by the NutFeder Consortium, a nonprofit that oversees the standard, security advisories, and certification. Privacy by design, data minimization, consent management, and revocation are core goals. Reception ranges from praise for cross-domain sign-on and user control to concerns about complexity and interoperability with legacy systems.

See also: SAML, OpenID Connect, OAuth 2.0, Decentralized identifiers.