- From: Christian Hommrich <christian.hommrich@trailprotocol.org>
- Date: Tue, 14 Apr 2026 13:00:33 +0200
- To: public-credentials@w3.org
- Cc: siri@helixar.ai, Amey Parle <amey.parle@gmail.com>
Hi Siri and all, The HDP approach resonates with me. Structuring delegation provenance as a cryptographically signed chain — anchored to the authorizing human, with each agent hop appending its own signed record — is an elegant solution to a problem the community has been circling for a while. The decision to make verification fully offline, requiring only a public key and session ID, is architecturally sound and avoids the availability coupling that plagues registry-polling designs. That said, I think there is a layer that HDP currently leaves open: the agent_id field in each delegation hop is a string — meaningful within a session, but carrying no cryptographic binding to a persistent, cross-session identity. If the same logical agent is deployed in a new environment, re-instantiated after a restart, or accessed by a verifier in a different organizational context, there is currently no standard way to establish that it is the same agent — or to answer how trustworthy that agent has been over time, independent of any single authorization chain. HDP answers "was this action authorized?". What is still missing is a durable answer to "is this agent who it claims to be?" This is the gap we are trying to close with the TRAIL DID method (did:trail). A did:trail identifier provides a resolvable, persistent anchor that an HDP agent_id field can reference — giving provenance chains a stable root that survives session boundaries and deployment changes. The TRAIL Trust Score (§7.3 of the spec — five independently verifiable dimensions covering identity verification, track record, information provenance, behavioral consistency, and third-party attestations) adds a longitudinal trust signal that complements HDP's per-session accountability. Cross-registry federation (§3.3) means this works across organizational and jurisdictional boundaries without requiring a single central authority. On that federation point: we just opened PR #13 on trail-did-method which codifies this normatively. §3.4 Trust Anchor Model defines a Federated Hybrid — Tier-1 Root Registries, Tier-2 Sub-Registries that delegate from Tier-1, and Tier-3 endpoint endorsements (web-of-trust, weighted into the Trust Score with a Risk Penalty discount). Verifiers maintain a local Trust List — no hard-coded single anchor. §8.7 makes W3C Status List 2021 the normative revocation mechanism, with exactly one authoritative registry per DID (declared via TrailRegistryService in the DID Document). Cross-registry score verification is deliberately non-trivial: verifiers fetch raw inputs from the origin registry's §7.3.4 endpoint and recompute the score locally, which eliminates score-laundering across federated registries. PR: https://github.com/trailprotocol/trail-did-method/pull/13 Amey Parle, who has been contributing to the trust score architecture and is co-architect on the federation model landing in PR #13, and I would be glad to explore how a did:trail reference could slot cleanly into HDP's agent_id field — or how TRAIL and HDP could publish a joint integration note for the CCG. Spec: https://github.com/trailprotocol/trail-did-method W3C DID Registry PR: w3c/did-extensions#669 Christian Hommrich TRAIL Protocol
Received on Tuesday, 14 April 2026 11:00:52 UTC