Protect PDF with Password
Add AES-128 password protection to any PDF in your browser. Set an open password (required to view), restrict printing and copying, or both. Your document never leaves your device.
How PDF Password Protection Works
PDF encryption works by encrypting the file content with a key derived from your password. When someone tries to open the PDF, the viewer asks for the password, derives the same key, and uses it to decrypt the content for display. Without the correct password, the content remains encrypted and unreadable.
The two types of PDF passwords serve different purposes. An open password prevents anyone from opening the file without it. A permissions password allows the PDF to be opened without a password but restricts what can be done — printing, text extraction, content modification.
Step-by-Step: Add Password to PDF
- 1Go to the PDF Protect tool.
- 2Upload your PDF by clicking or dragging it into the upload area.
- 3Enter your open password (required to view the PDF). Use a strong password — at least 12 characters with letters, numbers, and symbols.
- 4Optionally enable restrictions: prevent printing, prevent text copying, or prevent editing.
- 5Click Protect PDF.
- 6Download the password-protected PDF.
What Makes a Strong PDF Password?
✓ Strong Password
- 12+ characters
- Mix of uppercase and lowercase
- At least one number
- At least one symbol (!@#$%^)
- Not a dictionary word
- Example: T7#mK9@xPq2!
✗ Weak Password
- Common words (password, secret)
- Short sequences (1234, abcd)
- Personal info (name, date of birth)
- Company name or project name
- Same password as other accounts
Frequently Asked Questions
What type of encryption is used?â–¾
The PDF Protect tool uses AES-128 encryption via the pdf-lib library. This is the standard encryption used by Adobe Acrobat for password-protected PDFs. It is strong enough for confidential business documents.
What is the difference between an open password and a permissions password?â–¾
An open password (also called a user password) is required to open and view the PDF at all. A permissions password (owner password) allows the PDF to be opened without a password but restricts actions like printing, copying text, or editing. You can set either or both.
Can someone bypass the password?â–¾
AES-128 encryption is computationally expensive to crack. For practical purposes, a strong password (12+ characters, mixed types) makes the PDF secure. Weak passwords (common words, short sequences) can be cracked with freely available tools.
Does the PDF get uploaded to a server?â–¾
No. The entire password-protection process runs in your browser using pdf-lib. Your document and your password never leave your device.
Can I remove the password later?â–¾
Yes. Use the PDF Unlock tool on Irreva. Enter the password you set and the tool will produce an unlocked version.