If you have a .mac account and you enable encryption in iChat, you’ll get an autogenerated certificate in your Keychain.
Go to your Keychain to check if you do have it.
If you found it, you will be able to use it to encrypt your mails…
Just go to your Keychain preferences and check “Search .Mac for Certificates”.
Then you’ll see this little icon when composing a Mail in Mail.app from your .mac account.
PS: you must have the other person’s certificate to encrypt mail to it.
This Tutorial has been created by Melvin Rivera for the AllForces Blog:
Step 1: Get your account set up
If you don’t have an MSN or Yahoo account, you need to create one. A hotmail account could be used for MSN. Create an MSN account at passport.net.
Step 2: Get a Jabber Client App
Since iChat has only basic support for Jabber, you need a Jabber Client Application to create a Jabber account. We’re going to use Psi, one of many Jabber Client Applications.
Go to PSI’s website psi.affinix.com and select the Mac OS version of PSI and the mirror server closest to you.