Defense in Depth for AI Systems

Overview

Defense in depth applies multiple security layers so that if one fails, others still protect the system. For AI applications, this means validating at every boundary: edge, gateway, input, authorization, data, LLM, output, and observability.

Core Principle: No single security control should be the only thing protecting sensitive operations.

The 8-Layer Security Architecture

┌─────────────────────────────────────────────────────────────────────────┐
│  Layer 0: EDGE           │  WAF, Rate Limiting, DDoS, Bot Detection    │
├─────────────────────────────────────────────────────────────────────────┤
│  Layer 1: GATEWAY        │  JWT Verify, Extract Claims, Build Context  │
├─────────────────────────────────────────────────────────────────────────┤
│  Layer 2: INPUT          │  Schema Validation, PII Detection, Injection│
├─────────────────────────────────────────────────────────────────────────┤
│  Layer 3: AUTHORIZATION  │  RBAC/ABAC, Tenant Check, Resource Access   │