Encryption works best when the sender and receiver have previously communicated with each other via digitally signed emails, and when both choose and agree to exchange unclassified information that requires encryption.

NDU highly recommends that you DO NOT modify your MS Outlook settings to encrypt contents and attachments for ALL outgoing messages, as this may prevent many of your email recipients from opening your email. You can choose to “Encrypt” or “Sign” this email without affecting the settings for other outgoing email. To toggle ON or OFF a digital signature or encryption in MS Outlook, open a “New Email,” click on the “File” tab, and then click on the “Options” tab. NDU recommends that you toggle your digital signature and encryption options on and off depending upon the type of information you are sending via email message, although it is also acceptable to enable your digital signature for all outgoing email (See “MS Outlook Settings,” below). Sending Digitally Signed or Encrypted Email Messages If the email was sent without access to your current public key, you will not be able to open the email.

When you open the email, you may be prompted to enter your CAC PIN. A gold padlock will appear in the far right corner of the message. When you receive an encrypted email message, a padlock appears next to the subject line of the email in your inbox. Once the email is open, the signer’s name appears after “Signed By” in the header of the message, and a red ribbon will appear in the far right corner of the message. When you receive a digitally signed email message, a red ribbon appears next to the subject line of the email in your inbox. Receiving Digitally Signed Email Messages

NDU technically supports encrypting and digitally signing out-going email using Microsoft Outlook 2010 and a DoD-issued Common Access Card (CAC) on NDU's network email servers (' following instructions apply only to the use of MS Outlook 2010 on NDU network-based Exchange email servers using a CAC.

Add email signature in outlook 2010