Ring, ring.“Hello, this is Tom.”“Hi, Tom, I called to thank you.”“Thank me?”“Do you remember the data breach at the credit-rating agency Equifax last summer? You were among the 143 million people whose personal data were compromised.”“I was?”“That’s right. I gained access to your Social Security number, driver’s license number and credit card accounts.”“Who are you?”“Your worst nightmare, Tom.