PDF の保護
PDF にパスワードを設定
ブラウザで動作 · アップロード不要
このツールとページ内の説明は、現在は英語のみです。動作は同じで、すべてブラウザ内で実行されます。
Drag & drop the PDF to protect
or
One PDF file
Your files stay on your device. Nothing is uploaded.
Use at least 8 characters. There is no way to recover the password if you forget it, so keep it somewhere safe.
Restrictions (optional)
Choose what people who open the PDF may do. Most PDF apps respect these settings, but some ignore them.
お使いのブラウザはこのツールを動かすには古すぎます。更新するか、最新の Chrome、Edge、Firefox、Safari をお使いください。
- 何も端末から出ません
- サーバーによるサイズ制限なし
- 登録不要・透かしなし
- 無料
How to password protect a PDF
- Choose your PDF.
- Type a password twice. Optionally choose what people may do with the PDF (print, copy, edit…).
- Press Protect and download the encrypted PDF.
Good to know
- AES-256 encryption, the strongest standard PDF encryption, supported by all current PDF readers.
- Restrictions (no printing, no copying…) are respected by most PDF apps, but some ignore them; only the password itself truly protects the content.
- An optional second password allows changing the restrictions later.
- There is no way to recover a forgotten password. Keep it somewhere safe.
Your PDF stays in your browser
The file is read and changed on your device. Nothing is uploaded, so contracts, statements and IDs stay private.
よくある質問
How strong is the protection?
With a long password it is very strong: AES-256 can't be broken by guessing. Short, simple passwords can be guessed, so use at least 10 characters.
Is my password sent anywhere?
No. The PDF is encrypted in your browser; neither the file nor the password leaves your device.
Is my PDF uploaded?
No. Everything happens in your browser.