EBay DevCon: PayPal Goes Mobile

After a limpid reception in the US of PayPal's "Text2Buy" and "Text2Give" features, eBay has launched PayPal Mobile Checkout, a platform more closely mirroring the Web version.
On his blog, Williams explains further:

There are two API calls involved in PayPal Mobile Checkout. SetMobileCheckout works similar to SetExpressCheckout – it initiates a mobile checkout transaction. DoMobileCheckout completes the transaction, and is comparable to DoExpressCheckoutPayment. We’ve updated the Integration Center with details for developers on how the APIs and the checkout process works. 

Your next question was about security, wasn't it? At the