Signing messages with your Digital ID lets recipients of your messages verify that you sent the messages (not someone else) and that the messages were not altered or tampered with during the sending. Signing a message does not affect the contents of the message in any way, nor does it protect the message from being intercepted and read by someone else. Signing simply verifies that you sent the message and it remained intact. (To ensure that only the intended recipient can read the message, you must encrypt the message.)

Note: If you send a signed message to someone who does not use an e-mail application that supports encrypted e-mail, they can still read the message; your digital signature simply shows up as an attachment.

When reading a message, the signed icon indicates that a message was digitally signed. You can click the icon to store the sender's Digital ID, so you can easily send encrypted messages to that person.

You can sign individual messages or configure your security preferences to automatically sign all of the e-mail or newsgroup messages you send.