By Yohai Einav, VeriSign Senior Fraud Analyst
I was on my way to the airport, chatting with my cab driver. After I told him my overused joke about the peasant, the seigneur and the miraculous goat, he asked me for my profession. "Oh, fraud?", he said. "You know, I almost lost $7,000 to card fraud last year".
So the sanguine driver told me how his bank called him, warning him he had gone into overdraft. When he investigated this he found that his Visa card had recently been charged with $6,000. He called Visa, and they told him - "Sir, didn't you make two Â£1,500 transactions in London two weeks ago?"
No, he was never in London. No, he rarely uses the British Pound in Israel.
"Time out", I said. "Credit card issuers know that this could happen, and no way could these two transactions have passed without Visa noticing them". Firstly, the amounts were high, and secondly, the driver's card had a consistent pattern of transactions in only one...