Hackers could skim the PIN numbers from your smart phone.

Researchers have developed a new tool called the "PIN Skimmer" to see if it would be possible to tell what your PIN number is by taking control of your phone's camera and microphone in order to watch you enter the PIN and listen to the sound of the clicks.

Researchers tested the Google Nexus-S and the Galaxy S3 and successfully figured out a 4-digit PIN number 60% of the time.

They warn any phone with a camera could be vulnerable to hackers using tools like the PIN Skimmer.

They suggest using a longer PIN number or a thumbprint scanner to keep your phone locked.

- Rob Archer