Skip to content
DI
dummyipsum.com

Password protect PDF

Choose a PDF, set a new password and download an encrypted file that opens only when the password is entered. AES-128 encryption runs on your device, so the contract or payslip you protect is never uploaded anywhere.

Files never leave your device

Drop a PDF here or click to choose one

Choose a PDF and enter the new password twice.

How to password protect a PDF

  1. 1

    Choose a PDF

    Click Choose PDF or drag the file onto the page. It works in the browser on Windows, Mac, iPhone and Android, and the file is loaded only there.

  2. 2

    Type the password twice

    The new password needs at least 6 characters. Save it in your password manager right away, because without it nobody can open the file, you included.

  3. 3

    Click Protect PDF

    The file is encrypted with AES-128 right in your browser.

  4. 4

    Check and download

    The tool tries to open the result without the password and with the correct one, and compares page count, page size and selectable text with the original. The download appears only after the check passes.

What encryption the file gets

The file is saved as PDF 1.7 with AES-128 encryption. The opening password and the owner password are the same, and all permissions (printing, copying, editing) stay on, so the document works without limits once the password is entered. The tool will not encrypt a file that already has a password, which you can remove first with Unlock PDF, or a PDF/A file, which would lose its archival format.

When to put a password on a PDF

A password is worth it whenever you email a document with personal details: a contract, a payslip, a scanned passport or ID card, medical results or a tax form. If the message goes to the wrong address or someone gets into the mailbox, they still cannot open the attachment without the password.

Never send the password in the same email as the file. Share it by text message, a chat app or a phone call instead. Anyone who knows the password can print, copy or even unprotect the document, so a password protects the file on its way, not from the person you send it to.

Passwords, digital signatures and archiving

Encryption saves the file again, so an existing digital signature stored inside the PDF stops being valid. If the document needs both a password and a signature, protect it first and then sign the protected version in software that supports signing.

An encrypted file is only as safe as its password. For your archive, keep the unprotected original in secure storage, protect only the copies you send, and store the password in a password manager.

Privacy

All processing takes place in your browser. Your PDF is never uploaded to a server, and no data remains after you close the page.

FAQ

Is the password sent anywhere?
No. The password and the file stay in your browser tab, and encryption runs on your device. Neither the password nor the document content is sent to a server while the tool works.

What happens if I forget the password?
The tool never knows your password, so it cannot recover or guess it, and Unlock PDF asks for it too. Keep it in a password manager. Your unprotected original stays on your device, so at worst you lose the protected copy, not the document.

Can I block printing or copying?
No. The tool sets only an opening password and leaves all permissions on. Print and copy restrictions in a PDF are just a request to the viewer: many apps ignore them, and anyone who can open the file can take a screenshot. Real protection comes from the opening password.

How long should the password be?
The tool requires at least 6 characters, but a password of 12 or more characters, or a few unrelated words, is much safer. Use a password you do not use anywhere else, and send it to the recipient through a different channel from the file, for example by text message.

Will the protected PDF open in any app?
The file uses AES-128 encryption in PDF 1.7, which current PDF readers, web browsers and phone apps support. If a very old program cannot open it, update the program or try a different PDF reader.

How do I change the password of a PDF?
In two steps. First remove the old password with Unlock PDF, then protect the unlocked copy with the new password here. The tool refuses a file that already has a password, so a document never ends up with two layers of encryption.

Can I remove the password later?
Yes, with Unlock PDF, as long as you know the password. You get a copy without protection, and the protected file stays on your device unchanged, so you can keep both versions side by side.

Can I password protect a signed PDF?
You can, but the signature will no longer be valid. Encryption saves the file again, and a digital signature stored inside a PDF detects any change to the file. Protect the document first, then sign the protected version in software that supports signing.

Why can't I protect a PDF/A file?
The PDF/A archival format does not allow encryption, so the tool refuses such a file and shows a message. If you need a password, save the document as a regular PDF in the program that created it, protect that version and keep the PDF/A file for your archive.

How do I password protect a PDF without Adobe Acrobat?
Choose the file here, type the new password twice and click Protect PDF. AES-128 encryption runs in your browser tab, so you do not need Acrobat or any other software. The finished file opens with the password in Adobe Reader or any other current PDF reader.

Related Tools

More PDF tools that run in your browser, with no upload.

Unlock PDF

Remove a known password

Open

Remove PDF metadata

Strip author, dates and XMP

Open

Merge PDF

Combine PDF files in the browser

Open

Split PDF

Split a PDF into parts

Open

PDF tools overview

PDF pages

Images and PDF conversion

Whole document