A biometric authentication method for a computer system, the computer system comprising: a computer; and an authentication server, the biometric authentication method including steps of: extracting a first feature from the captured biometric information; generating a template polynomial for enrollment; extracting a second feature from the captured biometric information; generating a template polynomial for authentication; generating a correlation function for calculating a correlation between the template polynomial for authentication and the enrolled template polynomial; calculating a correlation value between the template polynomial for authentication and the enrolled template polynomial by using the generated correlation function, and determining based on the calculated correlation value whether or not the biometric information at the time of authentication coincides with the biometric information enrolled.