We’ve posted before about security keys—those little digital keyfobs that generate expiring security codes over and over and make it incredibly hard for someone to gain unauthorized access to your account. They’re a great idea, and now if you own an iPhone you can install a Verisign app that will work with Paypal and eBay, as well as about two dozen lesser known sites. It’s probably the easiest step you can take to vastly improve security on those accounts.