Security

Security Architecture

Guardian implements a defense-in-depth security model with multiple layers of protection:

┌──────────────────────────────────────────────┐
│              🔒 Application Layer             │
│  • Secure credential storage (Keychain/DPAPI) │
│  • Input validation & sanitization            │
│  • CSP-enforced script execution              │
└──────────────────────────────────────────────┘
                       │
┌──────────────────────────────────────────────┐
│             🔐 Transport Layer               │
│  • HTTPS/TLS for API communications           │
│  • Update checks via configured updater feed  │
│  • Authenticated update feed requests         │
└──────────────────────────────────────────────┘
                       │
┌──────────────────────────────────────────────┐
│              📦 Distribution Layer           │
│  • Optional code signing (build/distribution dependent) │
│  • Versioned release artifacts + metadata     │
│  • Updater signature verification (config dependent) │
└──────────────────────────────────────────────┘

Repository Strategy

Guardian uses a dual-repository model for maximum security:

Source Repository

• Contains all source code
• Access restricted to your development team
• No artifacts or binaries stored here
• Protected branches with code review requirements

Distribution Repository or Update Host

• Contains only signed release artifacts
• Release metadata in latest.json
• Release records for version history
• Public or internal access for download and update checks

Key Principle: Never expose source code in distribution locations. Only publish compiled, signed artifacts.

Signing Model

Release hardening depends on your build and distribution setup. Guardian supports common signing and verification patterns, but exact guarantees vary by platform and configuration.

Code Signing

Platform	Method	Certificate
macOS	Code signing / notarization	Build dependent
Windows	Code signing	Build dependent
Linux	Signature verification	Build dependent

Update Verification

The in-app updater can validate updates before applying them:

1. Download update package
2. Verify update (for example: signature checks depending on configuration)
3. Apply update if checks pass

If any verification fails, the update is rejected and the user is notified.

Secret Management

What to Protect

Secret Type	Storage Location	Never Store In
API Keys	Keychain/DPAPI	Plain text files
Private Keys	CI Secrets	Repository
Auth Tokens	Secure storage	localStorage

Configuration Best Practices

1. Use Environment Variables: For CI/CD, use encrypted secrets:

   # CI example
   env:
     ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
   

2. Rotate Keys Regularly: Set calendar reminders for key rotation

3. Audit Access: Review who has access to secrets quarterly

Data Protection

Local Data

Guardian stores these data types locally:

Data Type	Location	Encryption
Settings	App data folder	OS / filesystem dependent
Scan history	App data folder	OS / filesystem dependent
API credentials	System keychain	OS keychain encryption

Data Transmission

• API calls use HTTPS/TLS
• No telemetry data is collected without consent
• Scan results are processed locally by default; enabling external integrations may send selected context to third-party services you configure

Content Security Policy

Guardian enforces strict CSP rules:

default-src 'self';
script-src 'self';
style-src 'self';
img-src 'self' data: https:;
connect-src 'self' https://api.openai.com https://api.anthropic.com https://updates.guardian.example.com;
img-src 'self' data: https:;

This prevents:

• Cross-site scripting (XSS) attacks
• Unauthorized external connections
• Code injection attempts

Vulnerability Reporting

Found a security issue? Please report responsibly:

1. Use the issue tracker for the repository you are using (or your organization's private channel if this is an internal deployment).
2. Avoid posting exploit details publicly before a fix is available.

Do Not:

• Post vulnerabilities publicly before a fix is available
• Attempt to access other users' data
• Perform destructive testing

Security Checklist

Before deploying Guardian in your organization:

• Review and approve CSP settings
• Configure API keys securely (not in plain text)
• Enable auto-updates for security patches
• Review network access requirements with security team
• Document exception handling procedures