Sensor uses human breath for biometric security clearance

Combined with machine learning, this 'artificial nose,' built with a 16-channel sensor array, was able to authenticate up to 20 individuals with an average accuracy of over 97 per cent.

Researchers from Kyushu University's Institute for Materials Chemistry and Engineering, in collaboration with the University of Tokyo detail their findings in Chemical Communications.

There are a variety of biometrics that machines can use to identify people, including fingerprints, palm prints, voices, and faces to the less common options of ear acoustics and finger veins.

"These techniques rely on the physical uniqueness of each individual, but they are not fool proof. Physical characteristics can be copied, or even compromised by injury," said Chaiyanut Jirayupat, first author of the study. "Recently, human scent has been emerging as a new class of biometric authentication, essentially using your unique chemical composition to confirm who you are."

One such target has been percutaneous gas, which are compounds produced from skin. These methods have their limits because the skin does not produce a high enough concentration of volatile compounds for machines to detect.