Odor-based individual authentication

In response to growing demands for secure and user-friendly individual authentication methods, biometric technologies have seen widespread adoption, offering advantages over traditional password- or card-based systems. While current biometric systems primarily rely on physical traits such as fingerprints and facial structures, these modalities remain susceptible to theft and duplication. Human odor, composed of complex volatile organic compound (VOC) profiles unique to each individual, is a promising alternative based on chemical information that is inherently more difficult to forge. This review article presents a comprehensive overview of human odor-based individual authentication, focusing on skin and breath odors, which can be easily and noninvasively collected. We examine the origins and characteristics of human odor components and review measurement techniques, including the canine olfactory systems, gas chromatography-mass spectrometry (GC-MS), and gas sensor arrays. Furthermore, we discuss key challenges and potential solutions for implementing odor-based authentication systems, underscoring their promise for secure, noninvasive personal identification.