# AEGIS — Evidence Traceability Model

- **Document ID:** ARCH-43
- **Phase:** E.2 — Verification Methodology
- **Status:** Draft for review (post four-reviewer discipline)
- **Version:** 0.1
- **Date:** 2026-07-10
- **Owner:** Chief Security Architect

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## 1. Purpose

Codify how every assurance claim in AEGIS is bound to specific evidence. Implements Phase-E.2 mandate #7 (Assurance Evidence). If we say "secure, reliable, verified, resilient" — the phrase carries a link to the evidence proving it, or the phrase is not permitted.

## 2. Claim Registry

- **Assurance Claim Registry** — canonical, versioned list of claims AEGIS makes about itself.
- Each claim: `claim_id`, `text`, `scope` (subsystem or platform), `type` (security/reliability/privacy/performance/operational), `evidence_refs` (verification instruments), `owner`, `status`.
- Living document; grows with the platform.

## 3. Evidence Types

- **Test result** (unit / property / fuzz / integration / contract) — signed CI artifact.
- **Drill outcome** (chaos / recovery / IR / ceremony) — signed by IC + Auditor.
- **Metric threshold pass** — timestamped audit event referencing metric ID.
- **External audit finding** — signed by auditor.
- **Formal-verification result** — signed model + check log.
- **Red/purple team engagement report** — signed by engagement lead.
- **Threat-simulation report** (ARCH-39) — signed by runner.

Every evidence type has:
- Structured schema (verifier CLI can validate).
- Signature by producing role.
- Immutable storage (dual-store per ARCH-22).
- Retention per class.

## 4. Traceability Direction

- **Forward:** claim → evidence instruments → evidence artifacts.
- **Backward:** evidence artifact → claims supported.
- Both directions machine-queryable via the Knowledge Graph (ARCH-41).

## 5. Executable Claims

Where possible, claims are executable:
- Property tests attached to invariant claims.
- Drill runs attached to recovery claims.
- Metric thresholds attached to performance claims.
- Consistency checks attached to architectural claims.

Executable claims fail loudly when evidence is missing or stale.

## 6. Freshness

- Evidence has a **valid-until** window per type.
- **Stale evidence** cannot support a live claim; claim transitions to "unsupported."
- Freshness is a metric (ARCH-44).

## 7. Independent Verifiability

- Evidence artifacts sufficient for third-party verification where possible (per D-27-2 Reference Test Corpus).
- Audit chain + verifier CLI + published spec enable external verification.

## 8. Enforcement in Docs

- ARCH-* docs and public communications MUST cite evidence for absolute claims.
- The consistency checker (ARCH-41 C-3) enforces.

## 9. Independent Architecture Review

- **F-1.** *"Live" claims fluctuate with freshness.* UI/dashboards surface claim status.
- **F-2.** *Registry can bloat.* Governance rule + retirement of superseded claims.

## 10. Adversarial Architect Review

- **A-1.** *Attacker adds a claim with fake evidence.* Evidence is signed + verified; forgery caught.
- **A-2.** *Attacker suppresses evidence.* Dual-store + Layer-A audit + drift monitor.
- **A-3.** *Attacker exploits stale evidence.* Freshness enforcement + metric alerts.

## 11. Operational Reliability Review

- **O-1.** Registry lives in-repo.
- **O-2.** Evidence artifacts durable + retention-managed.
- **O-3.** Dashboards surface claim health.

## 12. Self-Critique

- **S-1.** *Small teams may struggle to keep every claim evidence-fresh.* Freshness windows tuned per claim class; explicit trade-off + Debt Register when necessary.
- **S-2.** *Claim wording may be gamed.* Reviewer discipline; auditor review; drift metric.

## 13. First-Target Analysis and Redesign

**Target:** the definition of "evidence." If "evidence" is defined loosely, weak artifacts pass. **Response:** each evidence type has a schema; artifacts must conform; verifier CLI validates; consistency checker rejects malformed evidence-links.

## 14. Decisions

### D-43-1. Assurance Claim Registry with typed, signed, retention-bounded evidence

- **Reason.** Mandate #7 (Assurance Evidence).

## 15. Change Log

- **0.1 (2026-07-10)** — Initial draft.