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Protect PDF with Password

Use this free Protect PDF with Password online tool to encrypt your PDF documents with a secure, custom password. It is built for students, teams, and professionals who need a clean result quickly. Upload, process, and download in a few clicks. Up to 50 MB per file.

Built & maintained by the OptaPDF Team Editorial standards Free · No sign-up · Files auto-deleted in 30 min
Secure TLS/SSL encryption 100% free, no signup Fast browser-based processing
📁

Drag & drop your files here

or click to browse from your device

Supported formats: .pdf (Max size: 50MB)

🔒 Secure temporary processing. Files are auto-deleted after 30 minutes.

Uploading file contents...

✓

Your File is Ready!

The processing step completed successfully. You can download your finalized file below.

📥 Download Processed File
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How to Use Protect PDF with Password

Complete your task in four clear steps.

1

Step 1

Upload the PDF document you want to encrypt.

2

Step 2

Enter and confirm your secure password.

3

Step 3

Click 'Protect PDF' to apply strong encryption.

4

Step 4

Download your secure, password-protected PDF.

Why Choose OptaPDF for Protect PDF with Password?

  • ✅ Uses secure AES encryption to lock and encrypt files.
  • ✅ Prevents unauthorized opening, printing, copying, or modifications.
  • ✅ 100% free with absolute file privacy and auto-deletion.

Security Guarantee

Your upload is protected with TLS/SSL encryption. Files are automatically and permanently deleted from our servers after 30 minutes. We do not read, share, or store your content. OptaPDF works on iOS, Android, Chrome, Safari, Edge, and desktop browsers without an app installation.

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Frequently Asked Questions About Protect PDF with Password

Get answers to common queries regarding security, speeds, and bounds of this tool.

We use standard high-strength PDF encryption to secure files, which is recognized by all compliant readers like Adobe Acrobat.
Upload your PDF to our Protect tool, enter a strong password, click encrypt, and download your secure PDF instantly.
No. Once encrypted, the PDF cannot be opened or viewed by anyone without typing the exact password you set.
The output file will follow our standard naming rule, e.g., x_protected.pdf.
No, OptaPDF's Protect PDF tool is 100% free and adds zero watermarks.
Yes, you can easily enter passwords and encrypt files from any mobile browser.
For security, we do not store your password. We recommend writing down or saving your password, as locked files cannot be unlocked without it.
Yes, files are processed temporarily in secure memory/folders and deleted automatically after 30 minutes.
The limit is 50MB.
No, the encryption is structural security metadata. Text and layout quality remain completely untouched.