PDF Merger
Combine multiple PDF documents in your chosen order.
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Protect PDF
Encrypt a PDF with an AES-256 opening password.
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How to use protect pdf
- Choose an unencrypted PDF and enter a strong opening password of at least eight characters.
- Process the file to apply AES-256 encryption.
- Test the password in your PDF reader and communicate it separately from the file.
Work through an example
Encrypt a PDF with an AES-256 opening password.
Protect PDF: a practical guide →Formats, privacy, and practical limits
Use a strong password and store it separately. Passwords stay in this tab and are never saved as preferences.
Files and generated results exist only for this tab session. Download any result you want to keep before leaving the page. Browsers may use temporary memory or disk cache while processing.
Frequently asked questions
What should I check before using Protect PDF?
Use a strong password and store it separately. Passwords stay in this tab and are never saved as preferences.
Are my uploaded files sent to a server?
This tool processes files in your browser. Its processing libraries and any required OCR language model are downloaded when needed; document contents are not uploaded to ERITHRA.