Browser Autofill
Input Fields Safe from Browser Autofill Leaks
Browsers autofill and autosave form data, often sending it to third-party services. SmartField uses cipher characters that the browser saves instead of real data. Autofill captures encrypted symbols.
The Attack
When browser autofill targets a standard HTML input, the attacker can read the plaintext value directly from the DOM:
// Browser Autofill attack:
document.querySelector('input').value
// "SensitiveData123" ← stolen
The Protection
With SmartField, the same attack returns encrypted data:
// Same attack against SmartField:
document.querySelector('smart-field').value
// "eyJ2IjoxLCJpdiI6..." ← AES-256-GCM encrypted
The attacker gets 600+ characters of encrypted gibberish. Useless without the server's RSA-2048 private key.
13 Security Layers
SmartField does not rely on any single defense. It combines 13 independent security layers:
- Closed Shadow DOM (shadowRoot = null)
- AES-256-GCM authenticated encryption
- RSA-2048 key exchange
- WeakMap data isolation
- Event propagation blocking
- Anti copy/paste/select/drag
- Cipher character display
- Anti-screenshot scrambling
- Hidden metadata (type, name, length)
- Value injection blocking
- Non-configurable properties
- Anti-bot architecture
- HTTPS enforcement
Implementation
<!-- 2 lines. That's it. -->
<script src="https://cdn.smartfield.dev/v1/smartfield.js"></script>
<smart-field type="password" encrypt-key="/api/sf-key"></smart-field>
Frequently Asked Questions
How does SmartField protect against browser autofill?+
Browsers autofill and autosave form data, often sending it to third-party services. SmartField uses cipher characters that the browser saves instead of real data. Autofill captures encrypted symbols.
Does this require changes to my server?+
Minimal. Install our server SDK (Node.js, Python, Java, Go, PHP, or Ruby). Call sf.decrypt() on the encrypted payload. Your existing authentication and business logic stays the same.
Does it work with React, Vue, and Angular?+
Yes. SmartField is a standard Web Component. It works with any framework or no framework at all.
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