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🔒 Security

Form Guardian is designed with security and privacy in mind. Learn how your data is protected.

🛡️ Core Security Features​

1. Automatic Password Exclusion​

By default, Form Guardian automatically excludes password fields from autosave:

// These fields are NEVER saved
<input type="password" name="password" />
<input type="password" name="confirm_password" />
<input type="password" name="old_password" />

Detection methods:

  • type="password" attribute
  • Field names containing "password" (case-insensitive)
  • Custom blacklist patterns

2. Sensitive Field Blacklist​

Built-in blacklist for common sensitive fields:

// Automatically excluded fields:
- password, passwd, pwd
- cvv, cvc, ccv
- ssn, social_security
- credit_card, card_number
- secret, token, api_key

3. Custom Blacklist​

Add your own sensitive fields:

useFormAutosave('my-form', {
  blacklist: [
    'input[name="ssn"]',
    'input[name="tax_id"]',
    '[data-sensitive="true"]',
    '.confidential',
  ],
});

Examples:

// Custom sensitive fields
<input name="ssn" /> {/* Excluded */}
<input name="tax_id" /> {/* Excluded */}
<input data-sensitive="true" /> {/* Excluded */}
<textarea className="confidential" /> {/* Excluded */}

🔐 Data Storage Security​

IndexedDB Encryption​

Form Guardian stores data in IndexedDB, which provides:

✅ Origin isolation - Data accessible only from same origin
✅ User-space storage - Stored on user's device
✅ Browser sandboxing - Protected by browser security
✅ No cloud sync - Data never leaves user's device

Storage Location​

Browser IndexedDB → Database: "form-guardian-db"
                 → Store: "drafts"
                 → Key: formId
                 → Value: { values, metadata }

Security implications:

  • ✅ Data stays local (no network transmission)
  • ✅ Isolated per browser profile
  • ✅ Cleared when user clears browsing data
  • ❌ Not encrypted at rest (OS-level encryption recommended)

Recommended: OS-Level Encryption​

For sensitive applications, enable OS disk encryption:

  • Windows: BitLocker
  • macOS: FileVault
  • Linux: LUKS/dm-crypt

🌐 Network Security​

No External Calls​

Form Guardian NEVER makes network requests:

// ❌ Form Guardian does NOT do this:
fetch('https://third-party.com/track', { data });
analytics.send('form-data', values);
cdn.upload('draft', formData);

Zero telemetry - No tracking, no analytics, no external dependencies.

Offline-First​

All operations happen locally:

✅ Save → IndexedDB (local)
✅ Load → IndexedDB (local)
✅ Clear → IndexedDB (local)

❌ No API calls
❌ No CDN uploads
❌ No third-party services

👤 Privacy & Compliance​

GDPR Compliance​

Form Guardian is GDPR-friendly by design:

✅ Data Minimization - Only form values stored
✅ User Control - User can clear drafts anytime
✅ Local Storage - No data processor involved
✅ No Tracking - Zero telemetry
✅ Transparency - Open source code

User Rights​

Users can exercise their rights:

// Right to erasure
await clearDraft('form-id');

// Right to access
const draft = await loadDraftCore('form-id');

// Right to data portability
const allDrafts = await getAllDrafts();
const json = JSON.stringify(allDrafts);

Cookie-Free​

Form Guardian does not use cookies. All storage is in IndexedDB.

🔍 Best Practices​

1. Audit Sensitive Forms​

Review what data is being saved:

useFormAutosave('payment-form', {
  onBeforeSave: (values) => {
    console.log('Saving:', values);
    
    // Verify no sensitive data
    if (values.cvv || values.password) {
      console.error('⚠️ Sensitive data detected!');
    }
  },
});

2. Use Whitelist for Sensitive Forms​

For forms with mostly sensitive data, use whitelist instead:

// Only save these specific fields
useFormAutosave('payment-form', {
  whitelist: [
    'input[name="billing_name"]',
    'input[name="billing_address"]',
    'input[name="billing_city"]',
  ],
  // Everything else is ignored
});

3. Set Appropriate TTL​

Don't keep sensitive drafts forever:

// Auto-delete after 1 hour
useFormAutosave('sensitive-form', {
  ttl: { hours: 1 },
});

// Auto-delete after 15 minutes
useFormAutosave('payment-form', {
  ttl: { minutes: 15 },
});

4. Clear on Submit​

Always clear drafts after successful submission:

const handleSubmit = async (data) => {
  try {
    await api.submit(data);
    await clearDraft(); // ✅ Clear sensitive draft
  } catch (error) {
    // Draft remains for retry
  }
};

5. Disable for Sensitive Forms​

For highly sensitive forms, consider disabling autosave:

// Don't use Form Guardian for:
- Credit card details (except billing address)
- Social security numbers
- Bank account numbers
- Medical records
- Legal documents requiring signatures

🚨 Security Considerations​

What Form Guardian DOES NOT Protect Against​

❌ XSS Attacks - Sanitize user input on server
❌ CSRF - Use CSRF tokens
❌ Session hijacking - Use secure session management
❌ Man-in-the-middle - Use HTTPS
❌ Physical access - Use OS-level encryption

Form Guardian focuses on draft storage security, not general web security.

Threat Model​

Protected against:

  • ✅ Accidental data loss (refresh, crash)
  • ✅ Unauthorized access via other origins
  • ✅ Data leakage via network

NOT protected against:

  • ❌ XSS vulnerabilities in your app
  • ❌ Compromised user device
  • ❌ Browser extensions with IndexedDB access
  • ❌ Physical access to unlocked device

🔬 Security Audits​

Verify Excluded Fields​

Test what's being saved:

const { getCurrentValues } = useFormAutosave('test-form');

// In dev console
const values = await getCurrentValues();
console.log('Saved fields:', Object.keys(values));

// Verify no password/cvv/etc

Review Dependencies​

Form Guardian has zero external dependencies:

{
  "dependencies": {} // No third-party code
}

Only peer dependencies (React, if using @form-guardian/react).

Inspect Source Code​

Form Guardian is open source:

git clone https://github.com/Tishkin/form-guardian-examples
cd form-guardian-examples

# Review source
cat packages/core/src/index.ts
cat packages/dom/src/index.ts
cat packages/react/src/index.ts

📋 Security Checklist​

Before deploying forms with autosave:

  • Verified password fields are excluded
  • Added custom blacklist for sensitive fields
  • Set appropriate TTL for drafts
  • Clear drafts on successful submit
  • Tested in dev console what's being saved
  • Considered using whitelist for sensitive forms
  • Documented privacy policy updates
  • Enabled HTTPS for production
  • Informed users about draft storage

🆘 Reporting Security Issues​

Found a security vulnerability?

Do NOT open a public issue.

Instead:

  1. Email: security@form-guardian.com
  2. Include:
    • Description of vulnerability
    • Steps to reproduce
    • Potential impact
    • Suggested fix (optional)

We'll respond within 48 hours.

📚 Related Documentation​

Your data security is our priority. 🔒