This chapter covered various ways to keep person-to-person communication on your Mac private. I began with an overview of email security and then moved on to explain how to prevent your passwords — as well as the contents of your incoming and outgoing messages — from being intercepted in transit. I explained how to digitally sign messages so the recipient can confirm the sender (and that the message hasn't been tampered with) and how to encrypt messages to prevent them from being read while stored on a mail server.
Because junk mail isn't merely annoying but can also contain viruses, phishing attempts, and other security threats, I described several ways of reducing spam as well as ways to discover more about a message's origins. I then showed how to encrypt instant messaging sessions as well as audio communication using voice over IP.