Protect PDF with Password: Add a password to a PDF with AES-256 encryption, privately. Input: PDF files and values you enter. Output: Results shown on the page and a downloaded file. Privacy: Runs in your browser: inputs and files stay on your device and are not uploaded.
How to password-protect a PDF
- Drop your PDF onto the box or tap to choose it.
- Type a password twice. Anyone opening the file will need it.
- Optionally open Permissions to block printing, copying text, editing or commenting, and set an owner password for changing those permissions later.
- Press Protect PDF and download the encrypted copy. Your original file is not changed.
Strong encryption, without uploading
The file is encrypted with AES-256, the strongest standard PDF encryption, supported by Adobe Acrobat, Preview on Mac, Chrome, Edge, Firefox and every modern PDF reader. The work is done by qpdf, a well-established open-source PDF tool, compiled to run inside your browser. Your document and password never leave your device, which matters for exactly the files people protect: payslips, tax returns, contracts, medical reports, bank statements and HR documents.
Choose a long password, ideally a phrase of three or four random words, and send it to the recipient by a different route than the file (for example, email the PDF and text the password). There is no way to recover a forgotten password, from us or anyone else. Permissions such as "no printing" are honoured by mainstream readers but are not real security on their own, because the content is visible once the file is open; the open password is what keeps the content private.
Which encryption is used?
AES-256 (PDF 2.0 / Acrobat X and later standard). It opens in all current PDF readers.
Is my file uploaded?
No. Your PDF is encrypted on your device; the qpdf engine comes from this site.
What if I forget the password?
It cannot be recovered. Keep the original unprotected file somewhere safe, or store the password in a password manager.
What is the owner password?
A second password that controls permissions such as printing and copying. If you leave it blank, a random one is generated so nobody can lift the restrictions.