It is wise to check the security of your bank website before pushing the button on any transactions. You can do this by double clicking on the lock at the bottom of any secure page. This will allow you to view the digital certificate. For example check the Comsec site.
Verisign is one of the main organisations that can issue digital certificates
It is quite simple to extend this securty to your own personal email. Go ahead and create a web of trust for your and your friends.
Banks have been looking at two-factor authentication (TFA) to further strengthen the security of internet banking. While not a form of digital certificate, TFA can drastically reduce incidence of online identity theft, and other online fraud, because the victim’s password would no longer be enough to give a thief access to their information. In Australia, the Commonwealth Bank is looking at introducing TFA for online banking in the first quarter of next year.
For more information, please see the Wikipedia entry on two-factor authentication.