Millions of dollars have been stolen from Citibank customers after thieves targeted a network of ATMs at 7-Eleven stores throughout the U.S.

To get the cash, the hackers gained access to individuals' personal identification numbers or PINs. For banks, the PIN is one of the most protected pieces of information. 

Identity theft happens more than one might think. According to the Federal Trade Commission, there are a lot of ways your identity can be stolen and South Dakota dad Jeremy Griffith knows this all too well.

A few years ago, he was attending a finance convention in Michigan. Griffith spent the day learning about identity theft when his banker called.

"He said, 'Are you in the U.S. right now?' I said, "Yeah. I'm in Detroit at a finance convention,'" recalled Griffith. As it turned out, his bank spotted some unusual charges from half-way across the world. Someone accessed his bank information online and spent nearly $3,000 in Pakistan.

"The next day it started really eating at me. Okay, they've got my bank information, what other... what other information do they have?" said Griffith.

Every year, nine million Americans have their identities stolen. Many make mistakes by not adequately protecting their PIN. Wells Fargo has several tips to keep your PIN safe.

• Protect it by keeping it private. Don't write it on your card or carry it in your wallet.
• At the ATM, shield the keypad so others can't see it.
• If you think those behind you in line could see your PIN, ask them to step back.
• Avoid using easy to guess PIN numbers, like a birthday, a phone number, or an address.

As for Jeremy Griffith, his bank helped him to get his identity back. Still, he learned how serious identity theft can be.

"It really hit home. It really made a person think that when... it can happen in Sioux Falls, SD," he said.

Question? Comment? News tip?
KSFY's Drew Sandholm can be reached by phone at (605) 373-7372 or by e-mail.