How to Password Protect a File in Adobe 9

By Shawn McClain

Adobe Acrobat's Public Document Format, or PDF, files are used to integrate text and media into a single document. If you are creating a document with proprietary or classified information, you need to password protect the file--even if it is just sitting on your computer. If your information isn't a secret, you can still place a password on the document to prevent anyone from making changes to it, once you send it out.

Step 1

Open the Adobe Acrobat 9 program by double clicking on the program icon. Click "File" form the toolbar at the top of the page and choose "Open." Find the file that you want to password protect by choosing the folder on the left side of the window and then double-clicking on the file on the right side.

Step 2

Click on the "Secure" button at the top of the window and choose "Encrypt with Password" from the drop-down menu. If a pop-up asks you to allow new security settings, just click on "Yes."

Step 3

Select a compatibility level in the drop-down box at the top if the security window. The levels are designated by the earliest version of Acrobat that can handle the encryption. The higher you set the encryption level, the better the overall encryption is. Anyone with a version of Acrobat or Reader earlier than the compatibility level will not be able to view the document.

Step 4

Choose one of the three options about how much of the document to protect. You can encrypt the entire document, the entire document except for metadata so search engines can still see the document, or only any file attachments. Most of the time you will choose to encrypt the entire document.

Step 5

Place a check mark next to "Require a password to open this document." Then type a password into the open box in the middle of the document. You can also place a check mark next to "Restrict Editing..." to simply protect the document from being edited. Enter a password just under that check box and choose the editing and printing settings that you would like to restrict. You can have both of these passwords set at the same time.

Step 6

Press the "OK" button to save your settings. Click "OK" again if a security pop-up appears. Enter your password, or passwords if you set both security settings, again and click "OK" to complete the process.

Tips & Warnings

  • If you set both a password to open the document and a password to edit the document, the edit password will also allow someone to open the document, but not the other way around.