# API Security

BlueNexus AI implements comprehensive API security measures to protect against threats and ensure secure access to platform resources.

## Authentication

### API Key Authentication

Primary authentication method for API access:

```bash
Authorization: Bearer YOUR_API_KEY
```

#### API Key Features

* **Unique Identifiers**: Cryptographically secure key generation
* **Scoped Access**: Granular permission scopes
* **Expiration**: Configurable expiration times
* **Rotation**: Regular key rotation support
* **Revocation**: Immediate revocation capability

#### Key Management

* **Generation**: Secure random key generation
* **Storage**: Encrypted storage in TEE
* **Transmission**: Secure transmission only
* **Usage Tracking**: Complete usage audit trail

### OAuth 2.0 Authentication

Industry-standard OAuth 2.0 implementation:

#### Authorization Code Flow

```mermaid
sequenceDiagram
    participant Client
    participant BlueNexus
    participant User
    participant Provider

    Client->>BlueNexus: 1. Authorization Request
    BlueNexus->>User: 2. Redirect to Provider
    User->>Provider: 3. User Authorization
    Provider->>BlueNexus: 4. Authorization Code
    BlueNexus->>Provider: 5. Exchange Code for Token
    Provider->>BlueNexus: 6. Access Token
    BlueNexus->>Client: 7. Access Token
```

#### Token Types

* **Access Tokens**: Short-lived (1 hour) API access
* **Refresh Tokens**: Long-lived token refresh
* **ID Tokens**: User identity information
* **Personal Access Tokens**: Long-lived API access

### Multi-Factor Authentication (MFA)

Enhanced security for sensitive operations:

* **TOTP**: Time-based one-time passwords
* **SMS**: SMS-based verification
* **Email**: Email-based verification
* **Hardware Tokens**: FIDO2/WebAuthn support

## Authorization

### Role-Based Access Control (RBAC)

Granular permission system:

#### Roles

* **Admin**: Full platform access
* **Developer**: API and development access
* **User**: Standard user access
* **Read-Only**: Read-only access

#### Permissions

* **api:read**: Read API resources
* **api:write**: Write API resources
* **api:admin**: Administrative access
* **connections:read**: Read connections
* **connections:write**: Manage connections
* **data:read**: Read data collections
* **data:write**: Write data collections
* **llm:read**: Access LLM services
* **mcp:read**: Access MCP servers
* **mcp:write**: Manage MCP servers

### Scope-Based Access Control

Fine-grained API access control:

```json
{
  "scopes": [
    "api:read",
    "data:write",
    "connections:read"
  ]
}
```

### Resource-Level Permissions

Per-resource access control:

* **Collection Access**: Per-collection permissions
* **Connection Access**: Per-connection permissions
* **MCP Server Access**: Per-server permissions
* **User Access**: Per-user permissions

## Input Validation

### Request Validation

Comprehensive input validation:

* **Schema Validation**: JSON schema validation
* **Type Checking**: Strict type validation
* **Length Limits**: Input length restrictions
* **Format Validation**: Format-specific validation

#### Example Validation

```json
{
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "minLength": 1,
      "maxLength": 100
    },
    "email": {
      "type": "string",
      "format": "email"
    }
  },
  "required": ["name", "email"]
}
```

### Sanitization

Input sanitization to prevent injection attacks:

* **SQL Injection**: Parameterized queries
* **XSS Prevention**: Output encoding
* **Command Injection**: Command sanitization
* **Path Traversal**: Path validation

## Rate Limiting

### Rate Limit Types

#### Per-User Limits

* **API Calls**: Requests per minute/hour/day
* **Data Operations**: CRUD operations per period
* **LLM Tokens**: Token usage per period
* **Connection Operations**: OAuth operations per period

#### Per-Endpoint Limits

* **Authentication**: Login attempts per minute
* **Data Creation**: Records per minute
* **File Upload**: Upload size and frequency
* **Search Operations**: Search queries per minute

### Rate Limit Headers

```http
X-RateLimit-Limit: 1000
X-RateLimit-Remaining: 999
X-RateLimit-Reset: 1640995200
X-RateLimit-Retry-After: 60
```

### Rate Limit Responses

```json
{
  "error": {
    "code": "RATE_LIMIT_EXCEEDED",
    "message": "Rate limit exceeded",
    "retry_after": 60
  }
}
```

## Security Headers

### HTTP Security Headers

Comprehensive security headers:

```http
Strict-Transport-Security: max-age=31536000; includeSubDomains
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
X-XSS-Protection: 1; mode=block
Content-Security-Policy: default-src 'self'
Referrer-Policy: strict-origin-when-cross-origin
Permissions-Policy: geolocation=(), microphone=(), camera=()
```

### CORS Configuration

Controlled cross-origin resource sharing:

```json
{
  "allowed_origins": ["https://app.bluenexus.ai"],
  "allowed_methods": ["GET", "POST", "PUT", "DELETE"],
  "allowed_headers": ["Authorization", "Content-Type"],
  "max_age": 86400
}
```

## Threat Protection

### DDoS Protection

Distributed denial-of-service protection:

* **Rate Limiting**: Request rate limiting
* **IP Filtering**: Malicious IP blocking
* **Geographic Filtering**: Regional access controls
* **Behavioral Analysis**: Anomaly detection

### Bot Protection

Automated bot detection and prevention:

* **CAPTCHA**: Challenge-response tests
* **Behavioral Analysis**: User behavior analysis
* **Device Fingerprinting**: Device identification
* **Machine Learning**: AI-powered bot detection

### Injection Attack Prevention

Protection against injection attacks:

* **SQL Injection**: Parameterized queries
* **NoSQL Injection**: Input validation
* **Command Injection**: Command sanitization
* **LDAP Injection**: LDAP query validation

## Audit Logging

### Logged Events

Comprehensive audit logging:

* **Authentication**: Login/logout events
* **Authorization**: Permission checks
* **Data Access**: Data read/write operations
* **Configuration**: System configuration changes
* **Security**: Security-related events

### Log Format

Structured logging format:

```json
{
  "timestamp": "2024-01-01T00:00:00Z",
  "event_type": "api_access",
  "user_id": "user_123",
  "ip_address": "192.168.1.1",
  "user_agent": "Mozilla/5.0...",
  "endpoint": "/api/v1/data/users",
  "method": "GET",
  "status_code": 200,
  "request_id": "req_123"
}
```

### Log Retention

* **Access Logs**: 90 days
* **Audit Logs**: 7 years
* **Security Logs**: 1 year
* **Error Logs**: 30 days

## Error Handling

### Secure Error Responses

Error responses that don't leak information:

```json
{
  "error": {
    "code": "INVALID_REQUEST",
    "message": "The request is invalid"
  }
}
```

### Error Codes

Standardized error codes:

* **400**: Bad Request
* **401**: Unauthorized
* **403**: Forbidden
* **404**: Not Found
* **429**: Too Many Requests
* **500**: Internal Server Error

## Security Monitoring

### Real-Time Monitoring

Continuous security monitoring:

* **Threat Detection**: AI-powered threat detection
* **Anomaly Detection**: Behavioral analysis
* **Incident Response**: Automated response
* **Alerting**: Real-time security alerts

### Security Metrics

Key security metrics:

* **Failed Authentication**: Failed login attempts
* **Rate Limit Violations**: Rate limit breaches
* **Suspicious Activity**: Unusual access patterns
* **Security Incidents**: Security events

## Best Practices

### For Developers

1. **Secure Coding**: Follow secure coding practices
2. **Input Validation**: Validate all inputs
3. **Error Handling**: Secure error handling
4. **Dependency Management**: Keep dependencies updated
5. **Secret Management**: Secure secret storage

### For Users

1. **Strong Passwords**: Use strong, unique passwords
2. **API Key Security**: Protect API keys
3. **Regular Updates**: Keep software updated
4. **Access Review**: Regularly review access permissions
5. **Security Awareness**: Stay informed about security

## Related Documentation

* [Security Overview](https://docs.bluenexus.ai/platform/security-and-privacy/security) - Overall security architecture
* [TEE Infrastructure](https://docs.bluenexus.ai/platform/security-and-privacy/tee-infrastructure) - Trusted execution environment
* [Data Protection](https://docs.bluenexus.ai/platform/security-and-privacy/data-protection) - Data security measures
* [Compliance](https://docs.bluenexus.ai/platform/compliance) - Compliance information
