Apple is looking for a "Payments Software Engineer" to work on a "next generation payment platform," which could be a clue about the secretive company's plans.
According to 9to5Mac, Apple is looking for someone to work on everything from payment devices to middleware, someone who has experience in e-commerce, banking, and technologies like EFTPOS and chip and pin systems. The goal is to "push the boundaries in new markets for Apple Retail."
It's likely that the first target Apple would have in mind for a payment system would be its own retail facilities, where it uses custom hardware on iPod Touches and iPads as smart mobile payment processing desks. But Apple's iBeacons system, even now being rolled out experimentally in stores as a true location-aware smart retail service, can be seen as an expansion of the EasyPay service the company has operated for a while in some of its own Apple Stores. Combined with Apple's Passbook app and the added user security given by fingerprint IDs on the iPhone 5S (and likely many future Apple devices), it's very likely that Apple may expand its iBeacon system into a true electronic alternative to standard credit card processing in stores.