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PDF Security Tool

PDF Locker

Add password protection to your PDF files. Secure invoices, contracts, and private documents with strong encryption — all in your browser.

Password Protection 100% Private Instant Always Free
Protect PDF with Password
Drop your PDF here
Drag & drop or click to browse · PDF only · Max 20 MB
Choose File
PDF
Your PDF and password never leave your device. All encryption happens locally in your browser.
Why Lock Your PDF?
Secure Sharing
Control who can open your PDF
Legal Compliance
Meet data protection requirements
Safe Email Attachments
Send sensitive files with confidence
Cloud Storage Security
Extra layer for stored documents
Frequently Asked Questions
Does this change the original PDF?
No. The tool creates a protected copy and leaves your original file unchanged. You'll download a new locked PDF.
Is the lock added in my browser?
Yes. Your PDF is processed locally using pdf-lib. The file and password never leave your device.
Should I use a strong password?
Yes. Use at least 8 characters with a mix of letters, numbers, and symbols for better protection.
Can I remove the password later?
Yes. If you know the password, use the PDF Unlocker tool to export an unlocked copy.
What encryption is used?
PDF 2.0 encryption with 128-bit AES. This is the standard for PDF password protection.
Is there a file size limit?
Maximum 20 MB per file. Most PDFs are well within this limit.
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