Some documents should only be opened by the people they're meant for, like payslips, medical letters, contracts and anything with account numbers on it. Protect PDF locks the file with AES-256 encryption, a strong method that modern PDF readers support. After that, anyone who opens it has to enter the password you set first.
How to use Protect PDF
- Add the PDF.
- Type a New password and repeat it in Confirm password.
- Select Protect PDF.
- Open the protected PDF to check the password works, then share the password through a different channel.
What the encryption does
- AES-256 across the document: The whole document, including its text, images and pages, is encrypted with AES-256, and the password is needed to decrypt and display it.
- One password for everything: The same password is used to open the file and to change its security settings, and no printing or copying restrictions are added, so anyone who has the password has full access.
- Why it's useful: Without it, the content can't be read, which is what makes protection useful for files sent by email or kept in shared folders.
Choosing and sharing the password
Encryption is only as strong as the password behind it.
- Length matters: A four-character password meets the minimum but can be guessed quickly by software, while a passphrase of several unrelated words is far stronger and easier to remember.
- Send it separately: Never send the password in the same email as the file. Tell the recipient by phone, in a text message or through a password manager.
- Nothing is stored: VelloDoc doesn't store passwords, so a forgotten password means the file can't be opened.
Before you protect
- Encrypt last, once the document is final, because most other tools need the password to work on it afterwards.
- Remove what isn't needed: Remove what the recipient doesn't need first: Redact PDF removes sensitive areas, and Remove Metadata clears author details.
- To reverse it: To reverse protection when you're authorized, use Unlock PDF.
- Where to read more: The PDF privacy guide explains how protection fits into safer sharing.
When people use Protect PDF
Payslips and HR letters
Send salary details and personnel letters so only the employee who knows the password can read them.
Medical and legal documents
Protect reports and case papers that pass through email or shared storage on their way to a client.
Financial statements
Encrypt statements containing account numbers before storing them in cloud folders.
Limitations to know
Protect PDF sets one password for opening and editing, with no separate printing or copying restrictions. Passwords must be at least four characters, a forgotten password can't be recovered, and protection doesn't remove hidden information from the document.
Protect PDF: common questions
How strong is the encryption?
Files are encrypted with AES-256, the strongest encryption method in the PDF standard. In practice, the strength of the password you choose matters most.
Can I stop people from printing or copying?
Not with this tool. It controls who can open the file. Once opened with the password, the document can be printed and copied.
What if I forget the password?
VelloDoc doesn't keep passwords, so the file can't be opened without it. Keep an unprotected copy somewhere safe, or store the password in a password manager.
Will the recipient be able to open it?
Yes, in any modern PDF reader, including Adobe Acrobat Reader, the PDF viewers built into browsers and the preview apps on phones and computers.
Can I protect a file that already has a password?
Yes. Enter its current password when the field appears, and the new password replaces the old one.