Federation Trust

APIS v2.0 Trust Model

APIS v2.0 uses realm-scoped trust decisions. A realm is the issuer-controlled namespace in did:passport:[realm]:[uuid].

Each realm maintains a trusted_issuers set with issuer IDs and key metadata. A credential is accepted only when:

• issuer signature is valid
• issuer is trusted in local policy
• passport status is active
• Machine Passport and trust-tier evidence meet local policy
• mandate policy permits requested action

Registry-Assisted Federation

Passport Alliance™ governance adds a signed issuer registry that can be consumed by verifiers and mirrored by members.

Canonical endpoints:

• GET /issuers.json
• GET /issuers.sig

Verifiers validate signature using Alliance root key and then apply local tier policy.

Tier-Aware Trust Policy

Example verifier policy:

{
  "trusted_issuer_levels": ["founding", "certified"],
  "minimum_agent_trust_tier": "tier2_5-dnssec",
  "allow_registered_in": ["sandbox"]
}

Compromise Handling

If an issuer is compromised:

1. Registry updates issuer status to suspended.
2. Updated registry is signed and published.
3. Verifiers reject newly checked passports from that issuer.

Design Principle

Anyone can implement APIS.

Alliance recognition controls ecosystem trust signaling, not protocol access.