How-To

Password Protect Your PDF Files

April 20, 2025·4 min read

Password-protecting a PDF adds a layer of security that prevents unauthorized access to sensitive documents. Whether you are sharing financial reports, legal contracts, or personal records, encryption ensures only intended recipients can open and read the file. Here is how to lock down your PDFs properly.

Two types of PDF passwords

PDFs support two levels of password protection. An open password prevents anyone from viewing the document without entering the correct password. A permissions password restricts specific actions like printing, copying text, or editing, while still allowing the document to be viewed. You can use either one or both for maximum security.

Choosing strong passwords

Use at least 12 characters with a mix of uppercase, lowercase, numbers, and symbols. Avoid dictionary words, birthdates, and common patterns. A passphrase like three random words joined with numbers is both strong and memorable. Never reuse passwords across different documents or services.

Encryption standards

Modern PDF encryption uses AES-256, which is virtually uncrackable with current technology. Older PDFs may use RC4 or AES-128, which are weaker. When protecting sensitive documents, always choose AES-256 encryption. SquishConvert uses AES-256 by default for all PDF password protection.

Protect PDFs with SquishConvert

Upload your PDF to SquishConvert, set your desired open password and permissions, and download the encrypted file. The entire process takes seconds and happens on secure servers. Your original file and password are never stored. Available with SquishConvert Pro.