A computer contractor stole credit card credentials, names and social security numbers of approximately 20 million South Koreans by copying them to a USB stick. This is the largest data theft in the history of South Korea. The data was unencrypted, which made it easy to steal, and the credit card firms weren`t aware of the theft until the authorities noticed them. The affected companies are KB Kookmin Card, Lotte Card, and NH Nonghyup Card, according to the report from Korea`s Financial Supervisory Service.”]