As of now True Key is supported on Chrome and Firefox browser on MAC and not safari. Safari browser has an limitation with add-ons. Hence its not supported but may be in the future we may get some information about TK application on safari browser. We will keep you posted.
I also would like to see it soon. My first year with TrueKey ends in February and there is still no Safari Plugin. TrueKey is great but not comfortable to use on a mac without another browser. I think about to leave TrueKey because of that issue