Biometric authentication, like fingerprint and iris scans, is an essential part of any spy movie, and trying to circumvent these security measures is often a central plot point. But these days, the tech isn’t just about snoopers, as fingerprint verification and facial recognition are now common features on many of our phones.
Now, researchers have developed a potential new scent option for the biometric security toolkit: your breath. In a report published in Chemical Communicationsresearchers from the Institute of Chemistry and Materials Engineering at Kyushu University, in collaboration with the University of Tokyo, have developed an olfactory sensor capable of identifying individuals by analyzing the compounds contained in their breath.
Combined with machine learning, this “artificial nose”, built with a 16-channel sensor network, was able to authenticate up to 20 individuals with an average accuracy of over 97%.
In the age of information and technology, biometric authentication is an essential means of protecting valuable assets. From the usual suspects of fingerprints, palm prints, voices and faces to the less common options of ear acoustics and finger veins, there is a variety of biometric data that machines can use to identify you.
“These techniques rely on the physical uniqueness of each individual, but they are not foolproof. Physical characteristics can be copied or even compromised by injury,” says Chaiyanut Jirayupat, first author of the study. “Recently, human scent has emerged as a new class of biometric authentication, essentially using your unique chemical makeup to confirm who you are.”
One such target has been percutaneous gas – compounds produced from your skin. However, these methods have their limitations because the skin does not produce a high enough concentration of volatile compounds for the machines to detect.
So the team turned to see if human breath could be used instead.
“The concentration of volatile compounds in the skin can be as low as several parts per billion or trillion, while compounds exhaled through the breath can be as high as parts per million,” Jirayupat continues. “In fact, human breath has already been used to identify if a person has cancer, diabetes, and even COVID-19.”
The team started by analyzing the subjects’ breath to see which compounds could be used for biometric authentication. A total of 28 compounds were found to be viable options.
Based on this, they developed an array of olfactory sensors with 16 channels, each of which can identify a specific range of compounds. The sensor data was then fed to a machine learning system to analyze the composition of each person’s breath and develop a profile to be used to distinguish an individual.
By testing the system with breath samples from six people, the researchers found that it could identify individuals with an average accuracy of 97.8%. This high level of precision remained constant even when the sample size was increased to 20 people.
“It was a diverse group of individuals of different ages, genders and nationalities. It is encouraging to see such accuracy across the board,” says Takeshi Yanagida who led the study.
Still, he admits more work is needed before it makes it to your next smartphone.
“In this work, we asked our subjects to fast for six hours before the test,” concludes Yanagida. “We have developed a good baseline. The next step will be to refine this technique so that it works regardless of diet. Fortunately, our current study has shown that adding more sensors and collecting more data can overcome this obstacle.”
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Material provided by Kyushu University. Note: Content may be edited for style and length.