When you make a credit-card transaction, the retailer stores the data in its computers. Credit-card encryption keeps the card numbers safe from cyber-thieves, but it isn't always successful. If hackers can crack the encryption, they can use your card to make purchases for themselves.
When a company stores your card number, it uses an encryption key that turns the information into an incomprehensible cipher. Without the key, stealing the data gets the hackers nowhere. The catch is that some companies store their encryption keys on easily hackable servers. Other companies have some of their data protected with older, weaker keys that can't withstand a concentrated cyber attack.
The Encrypted Chip
EMV cards -- named for Europay, MasterCard and Visa -- contain microchips that encrypt personal data. Buyers must enter a PIN or sign on the EMV scanner to let the purchase go through. The system encodes each transaction differently, so hackers can't reuse the data from one sale. When first introduced, the cards caught on in Europe but didn't generate much interest in America. As hackers became more successful at attacking retailers, America became more interested in EMV technology.
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