security-engineering

Security Engineering

Status: Active framework (v0.1.0). Tier 1/Tier 2 applied-security skills are available, with npm supply-chain hardening skills added for the May 2026 Mini Shai-Hulud response.

Applied-security framework for the design-time decisions that web-app threat modeling and CVE scanning don't catch: cryptographic primitive selection, chain-of-trust integrity, authentication-factor architecture, degraded-mode behavior, runtime secret hygiene, supply-chain trust, physical-access threats, and DFIR readiness handoff.

Why this exists

AIWG's existing security coverage (sdlc-complete/agents/security-architect, security-auditor, security-gatekeeper) is strong on application-layer threats — STRIDE on networked services, OWASP Top 10, CVE scanning, secrets-in-repo. It is silent on applied-cryptography review and chain-of-trust integrity, which is where most "we shipped insecure" outcomes actually happen.

This framework was scoped after a real-world gap analysis: a pre-production review of a hardware-backed offline secrets system surfaced four blockers and seven highs that no STRIDE/OWASP pass would have caught. They clustered into seven design-time pattern categories, all of which this framework addresses.

Boundary with sdlc-complete

This framework owns	sdlc-complete continues to own
Cryptographic primitive selection (AEAD, KDF, MAC, signature)	STRIDE threat modeling at system altitude
Chain-of-trust / bootstrap integrity	OWASP Top 10, CVE scanning, secrets-in-repo
Authentication factor architecture (have/know/are mapping)	Phase-gate compliance and control coverage
Degraded-mode (fail-closed vs fail-open) design	SAST/DAST tool execution
Runtime secret handling (fd passing, scratch surface, error paths)	Vulnerability management plan
Supply-chain trust beyond CVE scanning	SBOM generation
Physical-access threat modeling	Networked-service threat scenarios
DFIR readiness and handoff routing	Evidence collection, forensic analysis, IOC enrichment, forensic reporting

When the new agents land, the existing security-architect and security-auditor will be narrowed to delegate primitive-level review and chain-of-trust review to the applied agents (per the god-session rule).

Catalog format

Skills that name tools/libraries follow a three-part pattern:

1. Suggested default with rationale (e.g., "AEAD: prefer XChaCha20-Poly1305 via libsodium for new code in unconstrained environments — misuse-resistant nonces, audited C implementation, broad language bindings").
2. Vetted alternatives menu with selection criteria (e.g., when to choose AES-GCM, when to choose RustCrypto's aes-gcm-siv, when BoringSSL is the right call).
3. Research path for finding a better/newer fit (which RFCs, which audit reports, which standards bodies, what to grep in dependency manifests).

Skills never hard-pick a vendor product (no Keycloak/OpenBao/specific HSM models). They describe properties and patterns; the operator chooses the product against their constraints.

Planned scope (Tier 1 + Tier 2)

Tier 1 — highest leverage

• Skill: crypto-primitive-selection — AEAD/KDF/MAC/signature decision tree; anti-patterns (CBC-without-MAC, ad-hoc KDF, key reuse, PBKDF2-on-high-entropy, openssl enc without explicit flags)
• Skill: chain-of-trust-design — signed bootstrap, measured boot, "verify the verifier"
• Agent: applied-cryptographer — narrow primitive-choice review
• Rule: no-unauthenticated-encryption
• Rule: no-key-reuse-across-purposes
• Rule: no-adhoc-kdf
• Rule: crypto-flag-verification
• Template: cryptographic-decisions.md
• Template: chain-of-trust-design.md

Tier 2 — completes the gap

• Skill: auth-factor-design
• Skill: degraded-mode-design
• Skill: secret-handling-runtime
• Skill: supply-chain-trust
• Skill: supply-chain-hardening-quickstart
• Skill: npm-supply-chain-audit
• Skill: npm-release-age-gate
• Skill: physical-threat-modeling
• Skill: dfir-readiness — prepare incident evidence handling, chain-of-custody expectations, IOC readiness, and handoff to forensics-complete
• Agent: secure-bootstrap-reviewer
• Template: factor-design-rationale.md
• Template: degraded-mode-matrix.md
• Template: physical-threat-scenarios.md
• Extension: sdlc-complete/templates/security/threat-model-template.md — physical-access and trusted-host sections

Narrowing pass

• Audit + narrow sdlc-complete/agents/security-architect.md (delegate primitive review)
• Audit + narrow sdlc-complete/agents/security-auditor.md (delegate chain-of-trust review)

Quick start

# Once skills are implemented:
aiwg use security-engineering

# Run an applied-crypto review on a design doc
"applied crypto review of .aiwg/architecture/secrets-design.md"

# Generate a cryptographic decision record
"record crypto decision: AEAD selection for at-rest backup encryption"

# Harden an npm package after a supply-chain incident
"npm supply-chain audit and release-age gate review"

# Prepare a project for evidence-bearing incident response
"DFIR readiness for this service"

Standards referenced

NIST SP 800-57, 800-63B, 800-108, 800-208 · RFC 5869 (HKDF), 9106 (Argon2), 8446 (TLS 1.3) · OWASP ASVS 4.0, Cryptographic Storage Cheat Sheet · FIPS 140-3.

Tracking

• Epic and milestone: security-engineering-v1 on the origin Gitea remote
• Source motivation: ~/SECURITY-REVIEW-RESPONSE.md (local gap analysis, 2026-05-03)