docs/security_overview.md

Security Overview

Primary Responsibility: Detailed security architecture, threat model, and compliance

Multi-layer security architecture for the Enterprise AI Gateway.

Security Layers

┌─────────────────────────────────────────────────────────┐
│  Layer 1: Authentication & Rate Limiting                │
│  • API Key validation (X-API-Key header)                │
│  • Rate limiting (10 req/min, configurable)             │
│  • Token limit enforcement (4096 max input)             │
└─────────────────────────────────────────────────────────┘
                          │
                          ▼
┌─────────────────────────────────────────────────────────┐
│  Layer 2: Input Guard                                   │
│  • Prompt injection detection (pattern-based)           │
│  • PII detection (SSN, credit cards, emails, API keys)  │
│  • SQL/Command injection patterns                       │
└─────────────────────────────────────────────────────────┘
                          │
                          ▼
┌─────────────────────────────────────────────────────────┐
│  Layer 3: AI Safety (Gemini + Lakera Guard)             │
│  Primary: Gemini 2.5 Flash content classification       │
│  Fallback: Lakera Guard API                             │
│  Categories: Sexual, Hate, Harassment, Dangerous,       │
│              Civic Integrity, Prompt Injection          │
└─────────────────────────────────────────────────────────┘
                          │
                          ▼
┌─────────────────────────────────────────────────────────┐
│  Layer 4: LLM Router                                    │
│  • Provider authentication                              │
│  • Secure API communication (HTTPS)                     │
│  • Response validation                                  │
└─────────────────────────────────────────────────────────┘

Authentication

API Key Validation

• Header: X-API-Key: YOUR_API_KEY
• Environment variable: SERVICE_API_KEY
• Constant-time comparison to prevent timing attacks

Rate Limiting

Client-Side (Dashboard)

• 5 requests per 60 seconds
• Persisted in sessionStorage
• Reset button for demo purposes

Server-Side

• SlowAPI rate limiting
• Configurable via RATE_LIMIT environment variable
• Returns 429 on limit exceeded

Input Validation

PII Detection

Automatically detects and blocks:

• Email addresses
• Credit card numbers (4x4 digit patterns)
• Social Security Numbers (XXX-XX-XXXX)
• Tax IDs (XX-XXXXXXX)
• API keys (sk_, pk_, api_, bearer_ prefixes)

Prompt Injection Detection

Pattern-based detection for:

• "ignore all previous instructions"
• "disregard all previous instructions"
• "you are now"
• "system:" prefixes

AI Safety Layer

Primary: Gemini Classification

Uses Gemini 2.5 Flash to classify content into categories:

Category	Description
SEXUALLY_EXPLICIT	Nude, porn, explicit sexual content
HATE_SPEECH	Racism, discrimination, slurs
HARASSMENT	Threats, bullying, intimidation
DANGEROUS_CONTENT	Weapons, drugs, violence, self-harm
CIVIC_INTEGRITY	Election fraud, voter suppression

Fallback: Lakera Guard

When Gemini fails or times out:

• Endpoint: https://api.lakera.ai/v2/guard
• Detects prompt injections, jailbreaks, PII, toxicity
• Environment variable: LAKERA_API_KEY

Environment Variables

See Configuration Guide for complete environment variable reference.

Data Protection

• No persistent storage of user prompts or responses
• HTTPS/TLS for all API communications
• Environment variables for secrets (never in code)
• No logging of sensitive content by default

Compliance

• GDPR compliant (data minimization)
• OWASP API Security Top 10 aligned
• PII auto-detection prevents data leaks