Password-protect a PDF
Lock a PDF with a password before you email or share it. Anyone who opens it will need the password, and the encryption happens on your own device.
Your PDF and password are processed on this device and never uploaded. We don't see, store or log your files or passwords.
How it works
- Tap Choose file, or drop a PDF onto the page.
- Type a password of at least 6 characters.
- Tap Protect PDF.
- Download the protected PDF, or tap Share.
Why protect PDFs here
Most online tools need your document and your password on their server. Here both stay on your device: the PDF is encrypted by your own browser with AES-256, the strongest encryption the PDF format supports.
Choosing a strong password
Length matters most: 12 characters or more, such as three unrelated words, is far harder to crack than 8 mixed symbols. Send the password separately from the file, for example by phone or a different chat, never in the same email.
Good to know
Keep the password safe: if it is lost, the PDF cannot be opened, and we can't recover it. The protected file opens in every modern PDF reader, including browsers, Adobe Acrobat, Preview and phone apps.
Frequently asked questions
How secure is AES-256?
Very: with a long password it is not practical to break. Security depends mostly on the password you choose.
Can I remove the password later?
Yes. Use Unlock PDF with the same password.
Is my password uploaded?
No. It is used on your device to encrypt the file and then discarded.
Last reviewed: September 30, 2026
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