[Flash CS3 AS 2.0] Email encryption?

I’m working with a client on a Flash site and he would like his email encrypted so that he doesn’t get spam. We do not want an email form on the site, just a text link that says “Contact Us” that opens your email client. Right now I’m using the mailto: function but that leaves it open to spammers…right?

Does anyone know the best approach to doing this?

Thanks!