API Key Authentication System Documentation

1. Introduction

1.1 Overview

Secure authentication system for programmatic API access using tenant-specific API keys with role-based permission inheritance.

---

2. System Architecture

2.1 Database Schema

2.2 Core Components

Component	Description
API Key Service	Handles CRUD operations, role mapping, and transaction management
Authentication Middleware	Validates keys, extracts user context, and enforces permissions
API Key Controller	Manages REST endpoints and request/response handling

---

3. Authentication Workflow

---

4. API Key Management

4.1 Management Endpoints

Endpoint	Method	Description
/tenants/{tenantID}/apikeys	GET	List all API keys
/tenants/{tenantID}/apikeys	POST	Create new API key
/tenants/{tenantID}/apikeys/{apiKeyID}	GET	Get key details
/tenants/{tenantID}/apikeys/{apiKeyID}	PUT	Update key configuration
/tenants/{tenantID}/apikeys/{apiKeyID}	DELETE	Disable API key

4.2 Key Lifecycle Management

1. Creation

   • Generate cryptographically secure key (256-bit)
   • Store key hash (PBKDF2 with HMAC-SHA256)
   • Set default 90-day expiration

2. Rotation

   • Auto-generate new keys before expiration
   • Maintain legacy key validity for 7 days

3. Revocation

   • Immediate disablement via DELETE endpoint
   • Global invalidation within 60 seconds

---

5. Usage Guidelines

5.1 Authentication Header

GET /api/v1/resources HTTP/1.1
Host: api.example.com
Authorization: api_key sk_live_12ab34cd56ef78gh90ij12kl34mn56op

5.2 Permission Inheritance

// Example role mapping
{
  "apiKeyID": "key_12345",
  "roles": [
    "tenant.admin",
    "global.monitoring"
  ]
}

---

6. Security Implementation

6.1 Key Generation

const generateAPIKey = () => {
  const buffer = crypto.randomBytes(32);
  return buffer.toString('base64url');
};

6.2 Security Features

Feature	Implementation Details
Tenant Isolation	Mandatory tenantID in all requests
Rate Limiting	1000 requests/minute/key
Audit Logging	Full request metadata capture
Key Hashing	Argon2id with 64MB memory cost

---

7. Error Handling

7.1 Common Error Codes

Code	Scenario	Resolution
401	Invalid/missing API key	Verify key header format
403	Insufficient permissions	Check role assignments
429	Rate limit exceeded	Implement exponential backoff
500	Database connection failure	Retry with jittered delay

---