How to use Protect PDF
- 1Add the PDF you want to protect.
- 2Type a password twice, or click Generate to create a strong one (it is copied to your clipboard).
- 3Keep AES-256 selected, or pick AES-128 if the file must open in very old readers.
- 4Optionally switch on restrictions to block printing, copying or editing.
- 5Click Protect PDF and download the encrypted file.
Real encryption, checked before you download
This tool applies the standard PDF password security used by Adobe Acrobat: every page stream and text string is encrypted with AES-256 (or AES-128 if you choose). After encrypting, the tool re-opens the result to confirm it cannot be opened without the password and opens correctly with it.
AES-256 files open in Acrobat Reader X and later, Chrome, Edge, Firefox, macOS Preview and most modern apps.
Open password versus permissions
The open password is what actually protects your content. The optional permissions (no printing, no copying, no editing) are honored by Acrobat, Chrome and most viewers, but some software ignores them, so do not rely on them alone. If you set restrictions without an owner password, a random one is generated and shown so you can change the restrictions later.
Choosing a good password
- Use at least 12 characters; a few random words works well.
- There is no way to recover a forgotten password, so store it in a password manager.
- Send the password through a different channel than the file.
Frequently asked questions
Is my PDF uploaded to encrypt it?
No. Encryption is done by your browser and the file never leaves your device.
How secure is the protection?
The file is encrypted with AES-256, the strongest option in the PDF standard. Security then depends on your password, so choose a long one.
Can I stop people from printing or copying my PDF?
Yes. Turn on restrictions and choose what to block. Most readers respect these settings, but they are not enforceable in every program.
What if I forget the password?
It cannot be recovered. Keep the original unprotected file or save the password somewhere safe.
Will the protected PDF open on a phone?
Yes. iOS and Android PDF viewers and browsers support AES-256 encrypted PDFs and will ask for the password.