You can secure your iChat communications so that no one can listen in on your conferences. To have secure chats, you and your buddy must both have MobileMe subscriptions and must have enabled secure chatting.
MobileMe subscriptions include accounts that end in “me.com” and “mac.com.”
To set up secure chatting:
Choose iChat > Preferences, and then click Accounts.
Select the account you want to secure.
Free trial MobileMe subscriptions are not eligible for secure chatting.
Click Security, and then click the Enable button next to “iChat can enable encryption.”
As part of the setup process, you need to type an encryption password. This is the password you need to enter if you’re secure chatting on a second computer. This password may be different from your Mac OS X password.
When you enable secure chatting, MobileMe generates a Secure iChat certificate for you. If you and a buddy both have MobileMe certificates installed and you start a chat, a lock icon appears in the upper-right corner of the iChat window. Text, audio, and video are encrypted on your computer, sent across the Internet encrypted, and are not decrypted until they reach your buddy’s computer.
To view your Secure iChat certificate, open Keychain Access (located in the Utilities folder in the Applications folder), and click My Certificates in the Category list. Double-click the certificate that is the same as your MobileMe name.