Millions affected by South Korean credit card data theft Angry credit card customers have flocked to banks in South Korea to cancel their cards after a massive theft of personal data. The loss is believed to have affected around 100 million cards, reportedly including those of the president and UN chief Ban Ki Moon Prosecutors have arrested a 39 year old man, hired to improve client data protection but who stole information from three companies: Lotte Card, KB Financial Group and NongHyup Bank. Senior executives at the three firms have handed in their resignation, after being accused of failing to ensure adequate security. The stolen data was unencrypted. There are fears the information may have fallen into the hands of financial scammers. Customers say they have lost all confidence in the system. One woman said: "I can't trust Lotte anymore. Not only this but I cannot trust our whole nation anymore. When it comes to credibility, who am I supposed to trust, what am I supposed to believe? I honestly don't know anymore. Another woman added: "I cannot trust them. I wonder if an old person like me having a credit card is just my greed. I've lived my whole life based on credibility. South Koreans each have more than four credit cards on average. Citizens can generally live without carrying any cash as everywhere, including newsstands and buses, takes credit cards.