Do you use public computers? Maybe to check in on a flight at a hotel or a convention kiosk?

If so, criminals could be watching every move you make and recording every key you type, with the goal of swiping your personal information.

When John Wetmore travels for work, public computers are his lifeline for email access.

"My biggest worry when I'm using a public computer is, has someone installed spyware on it?" Wetmore said. "There's spyware on it, then someone can capture the key strokes and know my account and my password, and then I'm probably vulnerable."

He's right. Anyone using public computers may expose themselves to identity thieves.

There are no laws or regulations requiring public computers be secured against spyware programs.

"Criminals harvesting personal information off of public computers is an extremely prevalent crime in the United States," said Damon Petraglia, a forensic computer investigator.

Petraglia trains law enforcement agencies on computer security. He shows them how criminals can easily skim people's information from public computers.

First, Petraglia downloads a key-logging program onto a computer that records every key stroke. If he were a criminal, he'd leave the computer open for someone else to use and check later to see what he recorded.

An unsuspecting person might type in his login name and password, which can't be see on the screen as it's typed. But a keylogger report shows the user's screenname and password.

"There are hundreds and hundreds of different applications that criminals can use in a public environment to do nothing but record your data," Petraglia said.

"You wouldn't know that you became a victim from that," said Nikki Junker, of Identity Theft Resource Center.

Last year, the Federal Trade Commission got more than 250,000 identity theft complaints, and most victims don't have any idea how it happened.

To protect yourself at public computers, minimize the accounts you access, never type a password and never bank online. If you do use a password-protected site, change your email as soon as you get home.

Experts say it's good idea to change your password frequently to all accounts you have as a precaution, no matter where you log onto the web.