All conversions run locally in your browser. We do not upload or store your files.

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Protect PDF

Password-encrypt a PDF — requires password to open

All conversions run locally in your browser. We do not upload or store your files.Convert your file

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How to use this tool

Protect PDF

What this tool does

Protect PDF password-encrypts your document so only people with the password can open it. Use before emailing tax returns, medical records, financial statements, or HR files — especially when email itself is not encrypted.

Encryption runs locally with pdf-lib. Choose a strong password (minimum 4 characters) and share it through a separate channel (phone, Signal, not the same email).

Supported formats

Input: standard PDF (.pdf). Output: password-protected PDF requiring the password to open.

Password: minimum 4 characters. Same password used for user and owner access.

Step-by-step

Step 1: Upload your PDF.

Step 2: Enter a strong password (12+ characters recommended).

Step 3: Click Convert and download the protected PDF.

Step 4: Test opening with the password on another device before sending.

Limitations & tips

Browser encryption uses standard PDF password protection — compatible with Adobe Reader and most viewers. Does not restrict printing or copying separately (full owner permissions).

If you forget the password, the file cannot be recovered — store passwords securely.

Common use cases

Tax season: encrypt returns before email.

Medical records: password-protect patient summaries.

HR: secure offer letters and salary documents.

Privacy & local processing

Document Converter never uploads your file for conversion. Processing uses JavaScript in your browser tab — the same security boundary as editing a document offline. Closing the tab clears the in-memory copy unless you saved the output.

We may load analytics or ads when you visit the site, but those requests do not include your document bytes. For HR records, medical forms, or unreleased designs, local conversion avoids the third-party upload step that cloud converters require.

Browser-local vs cloud upload

Cloud tools like Smallpdf and iLovePDF receive your file via HTTP upload, process it on their servers, and return a download link. That model is convenient for public PDFs but adds privacy and compliance risk for sensitive content.

Document Converter runs pdf-lib, PDF.js, Mammoth, SheetJS, or Tesseract.js directly in your browser. Open DevTools → Network while converting: you should see no POST containing your file. You trade server-side CPU for device-side privacy — often the right choice for personal and workplace documents.

Real-world examples

An accountant password-protects a tax return PDF before emailing a client.

HR sends an offer letter PDF encrypted with a password shared by phone.

A doctor protects a medical summary PDF for secure patient delivery.

A CPA firm password-protects 50 client tax PDFs before secure email delivery.

Common questions

Is browser encryption secure?
Uses standard PDF encryption compatible with major readers. For top-secret documents, consider organizational tools with audit trails.
Can I set different open and owner passwords?
Currently one password for both open and permissions.
Forgot the password?
Encrypted PDFs cannot be recovered without the password. Keep originals unencrypted as backup.
Minimum password length?
4 characters minimum — use 12+ for real security.
Works on Mac Preview?
Yes — standard PDF encryption opens in Preview, Adobe, Chrome.
Protect then merge?
Merge first, then protect the final combined PDF.