Multifactor Authentication

Conventionally, authentication systems utilizing only the knowledge of ownership factors operate in pass/fail mode, i.e., the input data is either correct or incorrect. When it comes to using biometrics, the system faces potential errors during the biometric sample capturing, which was discussed previously in Section 3.4. We further elaborate on our proposed methodology from the crucial FAR/FRR perspective.

Typically, the FAR/FRR parameters of a sensor are provided by vendors based on the statistically collected data. For the MFA framework, we assume two possible decisions made during the user authentication phase, as it is displayed in Figure 8: $H_{0}$ ­– the user is not legitimate; or $H_{1}$ ­– the user is legitimate. These form the entire sample space of $P\left(H_{0}\right)+P\left(H_{1}\right)=1$. The risk policy is assumed to be handled by the authentication system owner who also sets up the distributions of $P\left(H_{0}\right)$ and $P\left(H_{1}\right)$.

Figure 8. MFA system mode. $P_{TH}$ is the selected threshold.