U.S. researchers say computer users who want to protect against identity theft should use a triple layer of software protection.

Computer users running all three -- anti-virus, anti-adware and anti-spyware software -- are 50 percent less likely than other to have their credit-card information stolen, computer scientists at Michigan State University reported Monday.

"When you think about antivirus software protecting you, you might think about it keeping your files safe and not losing your music and photos," Thomas Holt, MSU professor of criminal justice said. "The important thing we're finding here is that it's not just about protecting your files, but also about protecting you economically -- about reducing your chances of being a victim of identity theft."

Anti-virus, anti-spyware and anti-adware software each has a different function for keeping a computer safe, Holt said.

Anti-virus software detects and removes malicious software programs that can corrupt a computer, while anti-spyware and anti-adware programs are designed to protect against software that can covertly gather and transmit data about a user's Internet use, and possibly their passwords.

"You have a much better chance of not getting your credit card number stolen if you have all three forms of protective software," Holt said.