Is my PDF or password sent to a server?

No. The cryptographic key derivation and stream encryption execute 100% locally inside your web browser. Neither your document nor your secret password leaves your device.

Will the protected PDF open in Adobe Acrobat, Apple Preview, and mobile devices?

Yes. This tool outputs ISO 32000-compliant standard encrypted PDFs compatible with Apple Preview, Adobe Acrobat, Google Chrome, Safari, and mobile PDF viewers.

Password Protect PDF Offline — 100% Client-Side Encryption

Password Protect & Encrypt PDF

Add standard password protection to confidential PDF documents in your browser. Cryptographic encryption runs 100% offline in client memory — zero files uploaded to any server.

🔒

PDF Encryption Vault

🔒 100% IN-BROWSER

📑

Drop your PDF file here, or click to browse

Select any PDF to lock with a password. Zero file uploads.

⚡ Secure your sensitive clips and documents on macOS with L2Cache

L2Cache automatically flags sensitive clips (API tokens, passwords, private keys) with on-device intelligence, preventing confidential data from leaving your Mac.

🍎 Get L2Cache for Mac

Why You Should Never Upload Unencrypted PDFs to Web Converters

Protecting documents with passwords is a standard security requirement when sending W-2s, 1099 tax returns, payroll schedules, bank statements, and legal NDAs. Standard online PDF converters upload your unencrypted document across the internet, creating an immediate security vulnerability.

The 100% In-Browser Guarantee: This tool executes cryptographic key derivation and PDF stream encryption purely inside your browser memory. Enable Airplane Mode or disconnect from Wi-Fi to verify: the encryption executes completely offline with zero network connectivity.

Frequently Asked Questions

What happens if I forget the password?

Because the encryption uses standard cryptographic standards and is executed 100% offline, there is no master backdoor. Keep your password in a password manager.

Is this compatible with Apple Preview and Adobe Acrobat?

Yes. The output file uses standard PDF security handlers (ISO 32000 compliant) and prompts for a password in any desktop or mobile PDF reader.

Password Protect & Encrypt PDF

⚡ Secure your sensitive clips and documents on macOS with L2Cache

Why You Should Never Upload Unencrypted PDFs to Web Converters

Frequently Asked Questions

Related Developer Tools

PDF Merger

PDF Page Remover

JWT Decoder