The company has not confirmed a compromise but is notifying customers as a precaution.
The company would compete against Google, PayPal, Square and others if it enters this zone.
R'Pin and chip' smartcards may be next, not NFC smartphones, but liability questions remain.
A survey shows Internet shopping can be more eco-friendly if its procedures are accompanied by smart delivery logistics.
Many countries are still grappling with the issues of crypto-currencies such as Bitcoin, which is just the best-known of the virtual cash.
Payment card numbers may have been compromised, but the retailer says Social Security numbers, birth dates and customer PINs appear to be safe.
An integration with Shopkick will send deals to people's smartphones at the front entrance.
Gartner analysts expect worldwide tech spending to total $3.8 trillion in 2014, a 3.1 percent increase from 2013 spending of $3.7 trillion.
But the PINs were encrypted and therefore should be inaccessible to hackers, according to the retailer
The company blames delivery companies for the delays