How to Password Protect a PDF Free — Encrypt Any PDF in Your Browser
Some documents shouldn't be openable by just anyone — payslips, contracts, medical records, financial statements. Adding a password means only someone with the correct password can open the file at all, not just see a watermark or restriction notice.
Most tools that do this properly require an upload or a subscription. RightPDFKit encrypts your PDF with a password entirely in your browser. Your file — and your password — never leave your device.
How to password protect a PDF — step by step
Open RightPDFKit
Go to rightpdfkit.com and click Protect PDF in the sidebar under Security.
Upload your PDF
Drag and drop your document or click to browse. The file loads directly in your browser — nothing is uploaded to a server.
Set your password
Type a strong password and confirm it. The stronger the password, the more secure the encrypted file.
Encrypt and download
Click Protect PDF. RightPDFKit encrypts the file using AES-256 and downloads it instantly. Anyone opening it will need the password you set.
Open password vs permissions password
PDF security has two distinct types of password, and they do very different things:
| Type | What it controls | Use case |
|---|---|---|
| Open password | Required to view the document at all | Confidential files — payslips, contracts, IDs |
| Permissions password | Allows viewing but restricts printing, copying or editing | Shared documents where you want to limit actions, not access |
RightPDFKit's Protect tool sets an open password — the strongest form of protection, since the document cannot be opened at all without it.
How strong is the encryption?
RightPDFKit uses AES-256 encryption — the same standard used by banks, governments and enterprise security systems. A correctly chosen password combined with AES-256 makes brute-force attacks impractical within any realistic timeframe.
What makes a strong PDF password
- At least 12 characters — longer passwords are exponentially harder to brute-force
- Mix of upper, lower, numbers and symbols — avoid simple substitutions like "P@ssw0rd"
- No personal information — avoid names, birthdays, or anything findable on social media
- Unique per document — don't reuse the same password across multiple sensitive files
- Store it in a password manager — not in a text file next to the PDF itself
Common uses for password-protected PDFs
Payslips and financial statements
Protect payroll documents and bank statements before emailing them, so only the intended recipient with the password can open them.
Contracts and legal documents
Add a password before sending sensitive contracts or NDAs over email, where messages can sometimes be forwarded unintentionally.
Medical and personal records
Encrypt medical reports, ID scans or personal records before storing them in cloud storage or sending them to a third party.
Internal company documents
Protect HR files, internal reports or strategy documents that should only be accessible to specific people within an organisation.
PDF password protection tools compared
| Tool | Uploads file? | Encryption | Free? | Account? |
|---|---|---|---|---|
| RightPDFKit | No — local | AES-256 | Free | No |
| iLovePDF | Yes | AES-256 | Limited | No |
| Smallpdf | Yes | AES-256 | 2/day | Yes |
| Adobe Acrobat online | Yes | AES-256 | Limited trial | Yes |
| Microsoft Word (Save As) | No — desktop | AES-128/256 | Free | Microsoft account |
Frequently asked questions
Can I password protect a PDF that's already password protected?
You'll need to unlock it first with the existing password using RightPDFKit's Unlock PDF tool, then apply a new password using Protect PDF.
Does password protection stop someone from printing the PDF?
An open password prevents the file from being viewed at all without the password. Once opened with the correct password, normal printing and viewing permissions apply unless you also set specific permission restrictions.
Can I password protect a PDF on iPhone or Android?
Yes. Open rightpdfkit.com in Safari on iPhone or Chrome on Android, tap Protect PDF, upload your file, set a password, and download.
Is the password sent anywhere when I set it?
No. The password is used locally in your browser to encrypt the file using AES-256, and is never transmitted, logged or stored anywhere — including by RightPDFKit.
What's the difference between this and Unlock PDF?
Protect PDF adds a password to an unprotected file. Unlock PDF removes a password from a file when you already know the password. They're opposite operations, both free.