Credit and debit cards (payment cards) are the most common form of debt payment. According to the U.S. Census Bureau, there were 1.42 billion payment cards in the United States in 2000 and 1.48 billion in 2006 1. Furthermore, the same Census Bureau data projects that the total amount of annual commerce paid for with payment cards will reach $2.8 billion in 2010. Keeping the data stored on payment cards secure is a significant problem facing business globally. Companies risk considerable financial penalties and sometimes irreparable damage to their reputation when data breaches occur. For example, in March 2007, TJX, the parent company of TJ Maxx, Marshalls, and Bobís Store, reported that over several months more than 46 million credit and
debit card numbers were stolen as a result of data security breaches. The company settled the related lawsuits for $9.73 million. More damaging is the unknown amount of
business TJX lost due to the theft.