Free PDF Password Protector
Add password protection to any PDF with RC4-40 encryption, processed entirely in your browser. Your file is never uploaded to any server. Free, instant, no signup.
Drop a PDF here or click to upload
PDF files only · Max 20 MB
How it works
- Encryption runs entirely in your browser, your PDF is never uploaded to any server.
- Uses RC4-40 encryption (PDF Standard Security Handler, Revision 2), compatible with all PDF readers.
- The open password is required to view the file. The owner password restricts editing, printing, and copying.
Why Use This PDF Locker?
Built for privacy and compatibility, works with every PDF viewer.
RC4-40 Encryption
Industry-standard PDF encryption compatible with all major PDF viewers.
Never Uploaded
PDF is encrypted in your browser with pdf-lib, it never reaches any server.
Owner + User Passwords
Set both a user (open) password and an owner (permissions) password.
Instant Download
Encrypted PDF is ready to download immediately after processing.
When Should You Password-Protect a PDF?
Password-protecting a PDF is a simple but effective layer of access control. Common use cases include:
- Confidential reports: financial statements, business plans, or strategy documents shared with stakeholders.
- Legal contracts: NDAs, service agreements, and employment contracts distributed to multiple parties.
- Personal documents: passports, ID documents, medical records, or tax returns sent via email.
- Premium content: ebooks, courses, or reports sold online that should only be readable by the purchaser.
- Exam papers: tests or assessments that must remain sealed until a specific time.
Since this tool processes everything in your browser, it is especially safe for documents that must never be uploaded to unknown servers, such as government-issued IDs, banking documents, or client contracts.
Frequently Asked Questions
Everything about PDF password protection.
What encryption does this PDF locker use?
RC4-40-bit encryption, widely supported by all major PDF viewers including Adobe Acrobat, macOS Preview, and mobile apps. Compatible with all PDF readers.
Is my PDF uploaded to a server?
No. Encryption happens entirely in your browser using pdf-lib. Your PDF never leaves your device, safe for confidential documents.
Can I unlock a PDF with this tool?
No, this tool only adds password protection. To unlock a PDF, use Adobe Acrobat or macOS Preview with the original password.
What happens if I forget the password?
There is no recovery option. PDF encryption is irreversible without the password. Always keep a backup of the unprotected original file.
Will password-protected PDFs work on all devices?
Yes. RC4-40 encrypted PDFs are compatible with all major PDF apps. Adobe Acrobat, macOS Preview, iOS, Android, Foxit, and browser PDF viewers.