How to password-protect a PDF
Updated
To password-protect a PDF, open the Protect PDF tool on pdf.xyz, add your file, and set a password. The tool applies real AES encryption with qpdf, so only people who have the password can open the resulting PDF.
Protect PDF is a server tool: encryption runs on an encrypted, auto-deleting secure worker rather than in your browser. Your file uploads over an encrypted connection, and the worker deletes the input when the job finishes. The download link stops working after 60 minutes, and stored copies are erased by a daily storage rule.
No account is needed — open the tool, pick a file, choose a password, and download the encrypted copy. If you later need to remove the protection from a copy you can open, the Unlock PDF tool reverses the process using the password you know.
Open Protect PDFStep by step
- 1Open the Protect PDF tool.
- 2Add the PDF you want to protect — it uploads over an encrypted connection to the secure worker.
- 3Set the password that will be required to open the document. Anyone without it will not be able to open the protected copy.
- 4Run the tool. The secure worker applies AES encryption with qpdf and deletes the input when the job finishes.
- 5Download the protected PDF. The download link stops working after 60 minutes, so save the file right away.
- 6Confirm the protection: open the downloaded copy in your PDF viewer and check that it asks for the password before showing the document.
What the password actually does
Protect PDF adds a password and real AES encryption, applied with qpdf. The document itself is encrypted, which means the password is not a polite request — only people who have it can open the file. You start with a PDF and get back a PDF — one that simply refuses to open without the password.
Because the protection is encryption rather than a setting, it cuts both ways: the file is genuinely locked to anyone without the password, and it is just as locked to you if the password is lost. Read the limits below before you protect the only copy of something important.
Where your file is processed
Protect PDF runs on the server side, because the encryption uses qpdf on an encrypted, auto-deleting secure worker. Your PDF travels over an encrypted connection, the isolated worker applies the encryption, and the input is deleted when the job finishes. The download link stops working after 60 minutes, and stored copies are erased by a daily storage rule.
No account is needed at any step. Because the link is deliberately short-lived, download the protected file as soon as the job completes and keep your own copy.
Limits worth knowing
Each file can be up to 100 MB. The tool accepts PDF input and produces PDF output — it does not convert other formats.
The most important limit is the one you set yourself: the password. If it is lost, the Unlock PDF tool cannot help — it removes a password from a PDF you can already open, by entering the password that works, and it cannot recover or bypass a password nobody knows. Choose a password you can retrieve later, and record it somewhere dependable before you share the protected file.
When a password is not enough
A password controls who can open the document; it does not change what is inside it. Once someone opens the file with the password, everything in it is readable.
If specific content needs to be gone from the document itself — ID numbers, names, anything sensitive — use Redact PDF first. It covers the sensitive areas with solid boxes, then rebuilds each page as a flattened image so the text and vectors underneath are removed rather than hidden. Protect the redacted copy with a password afterward, and the two protections stack: the content is gone from the document, and the document only opens for people you gave the password to.
Common questions
Does password-protecting a PDF upload my file?
Yes. Protect PDF runs on a secure worker rather than in the browser, because the AES encryption is applied with qpdf. The file travels over an encrypted connection, the worker is encrypted and isolated, and it deletes the input when the job finishes.
How long does my protected PDF stay available?
The download link stops working after 60 minutes, and stored copies are erased by a daily storage rule. Download the result as soon as the job completes and keep your own copy.
What kind of encryption does Protect PDF use?
Real AES encryption, applied with qpdf. The output is an encrypted PDF that only opens for someone who has the password.
How large can my file be?
Up to 100 MB per file.
What if I forget the password later?
The password cannot be recovered through pdf.xyz. The Unlock PDF tool removes a password from a PDF you can already open — you enter the password that works and download an unprotected copy — but it cannot recover or bypass a password you do not know. Store the password somewhere dependable before you share the protected file.