JAC v0.5 — JEP/HJS Declared Dependency Chain Implementation Seed

JAC v0.5 is a JEP v0.6 and HJS v0.5 compatible implementation seed for declared dependency chains.

It aligns with:

• draft-wang-jac-02
• draft-wang-jep-judgment-event-protocol-06
• draft-wang-hjs-accountability-05

Positioning

JAC is a companion chain-composition layer over JEP and HJS.

JEP = atomic signed judgment events
HJS = accountability receipts, archive/privacy/evidence lifecycle
JAC = declared dependency chains over JEP/HJS objects

JAC v0.5 does not redefine JEP-Core:

• event object semantics;
• J/D/T/V verbs;
• event hash semantics;
• detached JWS over JCS;
• key resolution;
• validation modes;
• ext / ext_crit extension framework;
• failure-code semantics.

What changed from the earlier implementation

The earlier implementation used top-level task_based_on and extensions fields.

JAC v0.5 aligns dependency declarations with the JEP extension framework:

{
  "ext": {
    "https://jac.org/chain": {
      "based_on": "sha256:...",
      "based_on_type": "jep-event",
      "relation": "derived-from"
    }
  },
  "ext_crit": ["https://jac.org/chain"]
}

Added in v0.5

• JAC chain extension builder
• JAC chain validator seed
• JEP-compatible ext / ext_crit usage
• based_on, based_on_type, and relation fields
• declared chain root support
• declared break support
• observed-log assumption field
• chain fragment export
• schemas
• examples
• tests
• JAC/JEP alignment documentation
• release notes

Status

This is an implementation seed aligned with the core architecture of draft-wang-jac-02.

It does not yet claim full production conformance or complete coverage of all optional JAC deployment profiles.

Quick example

python jac_v05.py

Run tests

python -m pytest -q tests_jac_v05.py

Public drafts

• JAC: https://datatracker.ietf.org/doc/draft-wang-jac/
• JEP-Core: https://datatracker.ietf.org/doc/draft-wang-jep-judgment-event-protocol/
• HJS: https://datatracker.ietf.org/doc/draft-wang-hjs-accountability/