PDFパスワード保護 — 無料・プライベート
PDFファイルをパスワードで保護。ブラウザ内でローカル暗号化。
Private — encryption happens in your browser
Drop PDF to password-protect
PDF • Max 200MB
🔒100% Private — Your files never leave your device. All processing runs locally in your browser.
How It Works
Add password protection to any PDF using AES-256 encryption — the industry standard used by banks and governments. The encryption process runs entirely in your browser using WebAssembly, so your PDF and password never leave your device.
Choose a strong password, confirm it, and download the encrypted PDF. Recipients will need the password to open the file. The original formatting, fonts, and images are preserved exactly.
Features
- ✓AES-256 encryption — military-grade security standard
- ✓Password-to-open protection prevents unauthorized access
- ✓Preserves all formatting, fonts, and embedded images
- ✓Handles PDFs up to 200MB
- ✓Zero-knowledge — your password never leaves your device
- ✓Compatible with all PDF readers (Adobe, Chrome, Preview)
Frequently Asked Questions
The tool uses AES-256 encryption, the same standard used by banks, governments, and enterprise security systems.