Unsigned e-mails with attachments Published July 9, 2010 By 21st Communications Squadron PETERSON AIR FORCE BASE, Colo. -- The 21st Communications Squadron encourages users to follow weekly tips to further their computer knowledge. This week's tip concerns unsigned e-mails with attachments. Never open a link or attachment in an email unless the e-mail has been digitally signed. Doing so could infect your computer and the network with malware, exploiting our vital information. Please be aware of unsigned e-mails with links and attachments and never open e-mail from a non-trusted source. If you have questions contact the help desk at 554-comm or contact your wing information assurance office.