Starting Point

causes the "Messenger" page to appear. The two check boxes, shaded red on the messenger page, allow one to determine if all messages are to be automatically signed and/or encrypted.
 

If the "Sign mail messages, when possible" box is checked, a "certificate" always appears attached to the "security" icon, . This denotes that a message will be "signed" when sent. 

If both the "Encrypted" and Signed" options are checked, the "Security" icon, appears to be  "closed and locked" and has a "signed" certificate attached, . This indicates that messages will be both "signed" and "encrypted" when sent. 

Even though the mail client is configured to automatically sign and/or encrypt all messages, one may chose to not sign and/or encrypt any specific message.  When the "Message Options" icon is clicked,  , the "Address Field" is replaced with the "Message Options Display" illustrated in the following example. One can chose not to sign and/or encrypt the message being composed by unchecking the "Encrypted" box and/or the "Signed" box.