I have a paper claim with full account numbers and I must send a copy to three technicians. I’m not sure which digits …
Open the PDF file you want to encrypt in Adobe Acrobat Pro.
Select File from the top menu, then choose Properties.
In the Document Properties window, click the Security tab.
In the Security Method dropdown, select Password Security.
Under the Document Open section, check the option to require a password to open the document.
Enter a strong password in the Document Open Password field and confirm it when prompted.
CautionMake sure to remember the password; if lost, the document cannot be opened.
In the Options area, select the option to encrypt all document contents.
Best practiceEncrypting all document contents is recommended for maximum security when emailing sensitive PDFs.
Click OK to apply the password settings.
When prompted, re-enter the password to confirm.
Save the PDF to apply encryption and password protection.
Best practiceBefore emailing, test the PDF by reopening it to ensure the password works as expected.
After applying password protection, always save a backup of the original PDF in case you need to make changes later.
This runs in the Acrobat app - there is no separate API for this task.
Choose a Document Open Password if you want to stop anyone from seeing your PDF without permission. Choose a Permissions Password if you want people to view the PDF but not print it, copy text, or make changes. You can use both passwords for the highest security.
AES-128 and AES-256 are strong encryption standards that scramble your PDF's content. AES-256 is stronger than AES-128. This matters because it makes it very hard for unauthorized people to break the password and read your document. Using these methods keeps your confidential information safe.
Yes, when you set a Permissions Password, you can choose specific actions that are still allowed. For example, you can let others fill out form fields or add their signature while preventing them from printing or changing other parts of the document. This gives you flexible control.
Sending a PDF privately does not guarantee its security if it falls into the wrong hands. Password protection adds an extra layer of defense. Even if the file is accidentally shared or intercepted, only those with the password can access its content, protecting your sensitive information.
| Permission Type | Description | Use Case |
|---|---|---|
| High-resolution print | Allows printing the PDF with the best possible quality. | For documents meant for professional printing or archiving. |
| Low-resolution print | Allows printing but at a lower quality, usually for quick drafts. | For documents where you want to allow basic printing but discourage high-quality copies. |