Protect PDF
Add a password to your PDF with AES-256 encryption — without uploading it anywhere.
Drop the PDF you want to protectChoose a file to get started
Free tier supports files up to 50MB.
Processed in your browser — files never leave your device
How to Password Protect a PDF
Email attachments get forwarded, cloud links get shared, and laptops get lost. If a PDF contains anything private — a contract, a bank statement, medical records, payroll, or an unreleased business plan — a password is the simplest way to make sure only the right people can read it. This free tool encrypts your PDF with a password of your choice using AES-256 encryption, and it does the whole job inside your browser, so the document and the password are never uploaded to a server.
- 1
Upload your PDF
Choose the document you want to secure. It is opened locally in your browser.
- 2
Set a password
Type a password twice or generate a strong one with a single tap.
- 3
Choose restrictions (optional)
Decide whether people can print, copy, edit, comment on, or fill in the document.
- 4
Download the protected file
Your encrypted PDF downloads instantly and asks for the password whenever it is opened.
AES-256 encryption
The same strength of encryption trusted by banks and governments, by default.
Never uploaded
Encryption happens on your device. Your file and password never touch our servers.
Works everywhere
Protected files open in Adobe Acrobat, Chrome, Edge, macOS Preview, and mobile viewers.
Choosing a password that actually protects you
Strong encryption only helps if the password is hard to guess. Password cracking tools can try millions of common words, names, and dates every second, so "company2024" offers little real protection. Aim for at least 12 characters that mix upper- and lowercase letters, numbers, and symbols, or tap Generate to create a random 16-character password that is copied to your clipboard automatically. The strength meter updates as you type so you can see when a password is good enough.
Sharing the password safely
Never send the password in the same email as the protected file — if that message is intercepted or forwarded, both pieces travel together. Share the password through a different channel instead: a text message, a phone call, a messaging app, or a password manager's secure sharing feature. For recurring exchanges with the same person, agreeing on a password in advance works well.
Open passwords vs. permission restrictions
The PDF format supports two kinds of protection. The open password encrypts the entire document so nothing can be read without it. Optional restrictions control what people can do after opening the file, such as printing, copying text, or editing. Restrictions are useful for discouraging casual misuse — for example, stopping a price list from being copied into a competitor's quote — but they depend on the reader software respecting them, so treat them as a courtesy lock rather than a vault.
Why browser-based encryption matters
Many online PDF services upload your document to their servers to encrypt it, which means a private file passes through someone else's computer in readable form. PDFDoco encrypts locally on your own device using JavaScript, so the unprotected document never leaves your hands. That makes it suitable even for documents covered by confidentiality agreements or data-protection rules.
Pro tip: keep an unprotected original in a secure location and store the password in a password manager. If you ever lose the password, there is no way to recover the contents of the encrypted copy.
Frequently Asked Questions
How secure is a password-protected PDF?
Files are encrypted with AES-256, which is not practically breakable by brute force. In reality the password is the weak point: a short or common password can be guessed by cracking software. Use at least 12 characters mixing letters, numbers, and symbols — or the built-in generator — and the document is effectively unreadable without it.
What if I forget the password?
There is no back door. Because encryption happens in your browser, we never see or store your password, so we cannot recover it or unlock the file for you. Keep the password in a password manager and hold on to an unprotected copy of the original somewhere safe.
What is the difference between the open password and restrictions?
The open password is required to view the document at all. Restrictions — such as no printing or no copying — apply after the file is opened and are controlled by a separate owner password. Restrictions are honored by standard PDF readers, but they are less robust than the open password, so never rely on them alone for sensitive data.
Will the recipient need special software?
No. Password-protected PDFs are a standard part of the PDF format. Any modern PDF reader, including the one built into web browsers and phones, will simply ask for the password when the file is opened.
Does encryption change how my document looks?
No. The content, layout, fonts, and quality are exactly the same. Encryption only scrambles the stored data so it cannot be read without the password.
Can I remove the password later?
Yes. Use our Unlock PDF tool and enter the password to save an unprotected copy of the document.