KERI Protocol Specification Skill

KERI is a deterministic replicated state machine over a cryptographically rooted identifier namespace. It provides blockchain-equivalent security without global ordering, using append-only Key Event Logs (KELs), pre-rotation key commitments, and witness-based agreement (KAWA).

Architecture (7 Layers)

1. Identifier Theory — AIDs, SCIDs, autonomic namespaces
2. State Machine — KEL, key state, thresholds, rotation, delegation
3. Message Semantics — Events, receipts, field labels, seals, signing
4. Encoding — CESR native wire format (see cesr + cesr-encoding ref)
5. Validation Engine — Acceptance rules, duplicity, recovery
6. Availability — Witnesses, KAWA agreement
7. Discovery — OOBI, BADA, OKEA endpoint management

Message Types

KEL events: icp (inception), rot (rotation), ixn (interaction), dip (delegated inception), drt (delegated rotation). Receipt: rct. Routed: qry/rpy (query/reply), pro/bar (prod/bare — sealed data), xip/exn (exchange inception/exchange).

Reference Files

• event-model.md — Field labels, all 12 message field orders, 7 seal types with count codes, signature attachment model, dual-index verification, config traits, delegation two-way peg
• cesr-encoding.md — CESR native encoding: version field (0O), datetime/threshold/route encoding, CESR field orders for all message types, seal count codes
• key-state-machine.md — Pre-rotation, fractionally weighted thresholds, general/reserve/custodial rotation, SQAR, cooperative delegation, keypair lifecycle, attack taxonomy, AID derivation
• validation.md — Verification vs validation, role-locality matrix, event classes, duplicity detection, first-seen policy, superseding recovery (Rules A/B/C), KAWA fault parameters and witnessing policy
• routing-discovery.md — OOBI variants and verification, BADA monotonic update policy, RUN (no-delete), OKEA endpoint authorization, JIT/NTK discovery

Key Invariants

• One KEL per AID, append-only, doubly hash-chained
• “First seen, always seen, never unseen”
• Rotation requires dual threshold: current kt AND prior-next nt
• Delegation requires two-way peg: SealEvent in delegator + di in delegatee
• Empty n list at inception = non-transferable; at rotation = abandoned
• Witnesses MUST be non-transferable AIDs
• All signatures attach via CESR codes, never as top-level fields