How to Apply Password Security in Adobe Acrobat CS6
Selecting the Encrypt with Password option from the Encrypt button in the Protection section of the Tools panel in Adobe Acrobat CS6 limits access to the PDF file. Only those who know the password can open the file. However, documents are only as secure as the passwords that protect them.
To guard against discovery of a password, use passwords that are eight or more characters in length and include at least one number or symbol and vary the case of the characters. Avoid using words in the dictionary and short passwords. For example, the password Minneapolis is less secure than M1nneap0lis, which mixes numbers, letters, and includes an uppercase character along with lowercase characters.
To apply password security to a file, follow these steps:
With a PDF file open, choose Tools→Protection →Encrypt→Encrypt with Password.
Click Yes when the Applying New Security Settings dialog box appears, verifying that you want to apply security to this PDF.
The Password Security – Settings dialog box appears. You can click the Do Not Show This Message Again checkbox if you do not want this message to appear every time you are securing a PDF file using Acrobat.
Select Acrobat 7 and Later from the Compatibility drop-down list.
Although Acrobat X provides more robust security, few people are using version X of Acrobat, making it difficult to distribute the file with this high level of security.
Select the Require a Password to Open the Document check box.
Enter a password in the Document Open Password text box.
Acrobat provides you with guidance as to the strength of the password you select, letting you know whether the password can easily be bypassed. You can also add more security settings. Or you can use this setting as the only security to be applied to the document.
If password protection is the only security measure you apply to the document, authorized users can access the document by entering a password. Users with the password may also be able to edit or print the document unless you apply additional security measures.
Confirm the password and click OK again. Acrobat warns you that Adobe software honors the security settings, but other tools may allow you to bypass the security. Click OK again and the dialog box closes.
Save, close, and then reopen the PDF file.
A password dialog box appears asking for the password to access the secured file. Every time a user accesses the file, he or she will be required to enter a password.