Protect PDF
Add a password to your PDF file
Click or drop a PDF hereChoose a PDF
Permissions (what people who open the file may do)
About Protect PDF
Protect PDF encrypts your PDF with AES-128 so that it asks for the password you set before it opens. Under Permissions, you decide what people who open it may do: print (normally, at low resolution only, or not at all), copy text and images, edit, add comments, fill in form fields, and insert, rotate, or delete pages. Unless you change them, printing and form filling are allowed and the other four are blocked. A separate permissions password protects these settings; left empty, a random one nobody knows is used. The file is encrypted inside your browser before you download it.
How to password-protect a PDF
- 1Choose the PDF to protect.
- 2Type the open password in "Password".
- 3Open "Permissions (what people who open the file may do)" to change what is allowed and, if you wish, set a permissions password.
- 4Click "Protect PDF", then "Download" to save the -protected.pdf file.
Formats and limits
- Input
- Encryption
- AES-128 for every file
- Default permissions
- Printing and form filling allowed; copying, editing, comments, and page changes blocked
- Permissions password
- Yours or a random one; it must differ from the open password
- Result
- Your file name followed by -protected.pdf
Where your file is processed
The password and the PDF stay in your browser: @cantoo/pdf-lib encrypts the file locally and nothing about it is uploaded. The site keeps no copy of your password, so it cannot help you recover a forgotten one. When you leave the permissions password empty, its random replacement is also created in the browser, with the browser's cryptographic random generator.
Frequently asked questions
How strong is the encryption?
128-bit AES for every file. The file header is raised to PDF 1.7 first so older files do not fall back to the weak RC4 cipher, and the deprecated AES-256 revision 5 is not used. A long, unusual password matters more than the cipher.
Can people copy text from my protected PDF?
No, not by default: copying is blocked, like editing, comments, and page changes. Open Permissions before you click Protect PDF and check Copy text and images, or any other right you want to allow.
Can someone remove the restrictions?
Yes, anyone who knows the open password can. Permissions are rules that PDF readers follow, not a lock: tools such as our Unlock PDF remove them once the file can be opened. Only the open password keeps the content unreadable.
Can I use the same password for opening and for permissions?
No. The tool refuses it, because anyone who can open the file could then change the permissions. Leave the permissions password empty to get a random one that nobody knows.
Tips and tricks
- ✓To remove the protection later, open the file in Unlock PDF with the same open password.