Use the Appliance Settings: Attachment decryption page to configure a list of password candidates, list of keyword candidates, and a list of ignored word candidates the Email Security — Server appliance can use to decrypt password-encrypted malware objects.
To configure attachment decryption settings:
Click Settings and then select Appliance Settings.
Click Attachment decryption in the sidebar.
(Optional) Use the controls at the top of the page to define the scope of the changes.