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14.11 Security Architecture & Zero-Trust Infrastructure
1. Plain English Overview
Security architecture establishes end-to-end protective mechanisms across identity verification, transport encryption, privilege separation, and defensive barriers to prevent data breaches, unauthorized device tampering, and infrastructure takeover.
2. Usage in Cooking Nexus
- Passwordless Identity Tokens: HMAC-SHA256 signed JSON Web Tokens with strict 15-minute expirations ([controllers/authController.js:L8](file:///Users/avishjain/avishjain9-repos/26-cooking-nexus/controllers/authController.js#L8)).
- Data Layer Sanitization: Mongoose schema projections (
.select('-password')) preventing credential leakage ([services/memberService.js:L3](file:///Users/avishjain/avishjain9-repos/26-cooking-nexus/services/memberService.js#L3)). - Prompt Injection Defense: Privileged system instructions in [chef-ai/index.ts:L8-L31](file:///Users/avishjain/avishjain9-repos/26-cooking-nexus/27-kitchen-companion-pro/supabase/functions/chef-ai/index.ts#L8-L31).
3. Defense-in-Depth Security Topology
4. Authentication Architecture Comparison
| Auth Pattern | Credential Storage | Breach Risk | Revocation Speed | Mobile / IoT Fit | Fit for Cooking Nexus |
|---|---|---|---|---|---|
| Magic Link JWT (Chosen) | Ephemeral Signed Token | Ultra-Low (No stored passwords) | Fast (15m expiry) | Frictionless for cooks | Optimal for consumer MVP |
| Password + Argon2 | Hashed & Salted DB field | High (Credential stuffing) | Requires password reset | Cumbersome with messy hands | Outdated for modern web |
| OAuth2 / OIDC (Google/Apple) | External ID Provider | Ultra-Low (Delegated) | Instant via IdP | Excellent (One-tap biometric) | Planned next phase |
| Stateful Sessions (Redis) | In-Memory Session ID | Low | Instant (Delete session key) | Requires sticky cookies | Good, but higher server RAM |
| Hardware Mutual TLS (mTLS) | X.509 Client Certificates | Zero (Cryptographic hardware) | Certificate Revocation List | Mandatory for range cameras | Production IoT standard |
5. Trade-offs Accepted
- Magic Link Email Delay: Relying on email delivery adds a 5 to 15-second delay compared to typing a password. We accepted this because cooks log in infrequently and benefit from zero password friction.
6. What Breaks First at Scale?
- At 10x: Storing secrets in plaintext
.envfiles becomes a severe audit risk when onboarding new engineers. - At 100x: Token replay attacks: if an attacker intercepts a valid magic link within its 15-minute window, they can authenticate unless the token is single-use invalidated in Redis.
- At 1,000x: Coordinated bot distributed denial of service targeting the
/api/auth/loginendpoint.
7. Senior Engineer Improvements
- Single-Use JTI Revocation: Include a unique
jti(JWT ID) in every magic link token. Upon first verification, storejtiin Redis with a 15-minute TTL; reject any subsequent attempts with the same token ID. - Secrets Rotation: Migrate
JWT_SECRETandMONGO_URIto AWS Secrets Manager with automated 30-day cryptographic key rotation.
8. Spoken Interview Answer (30 Seconds)
"Our security architecture follows a zero-trust model. We completely eliminated password vulnerability vectors by using 15-minute single-use signed JWT Magic Links, meaning our database contains zero password hashes to compromise. For IoT hardware, all kitchen optical classification is executed on local camera hardware, sending only abstract JSON hazard metadata to our cloud backend to ensure raw home kitchen video never leaves the premises."