DoCoMo Launching Mobile Credit Card

I guess DoCoMo is adding Credit Card to their prepaid card. I see no mention of a security feature but their has to be one.

Wireless Watch Japan: "DoCoMo Launching Mobile Credit Card
Wireless News :: New Tech & Services
WWJ Editors, 8 November 2005
DoCoMo's Osaifu keitai (mobile wallet) line of cellphones will soon have their own branded virtual credit card for mobile payments. The iD card ('i' as in iMode) will be launched on December 1, 2005 and will enhance existing credit card services by giving credit card owners the option of making payments via a DoCoMo wallet phone linked to the card, in addition to conventional payments with their plastic credit card. That means charges through the phone will automatically be deducted from the user's designated credit card. Just waving the phones in front of dedicated reader/writers at stores will start the payment process.

A good article explaining more can be found here.