An example of two-factor authentication is fingerprint and a smart card. Two-factor authentication is a type of authentication that requires two different factors or methods to verify the identity or the credentials of a user or a device. The factors or methods can be categorized into three types: something you know, something you have, or something you are. Something you know is a factor that relies on the knowledge of the user or the device, such as a password, a PIN, or a security question. Something you have is a factor that relies on the possession of the user or the device, such as a smart card, a token, or a certificate. Something you are is a factor that relies on the biometrics of the user or the device, such as a fingerprint, a retina scan, or a voice recognition. Fingerprint and a smart card are an example of two-factor authentication, as they combine two different factors: something you are and something you have. Retina scan and a palm print are not an example of two-factor authentication, as they are both the same factor: something you are. Magnetic stripe card and an ID badge are not an example of two-factor authentication, as they are both the same factor: something you have. Password and CAPTCHA are not an example of two-factor authentication, as they are both the same factor: something you know. References: CISSP All-in-One Exam Guide, Eighth Edition, Chapter 5, Identity and Access Management, page 685. Official (ISC)2 CISSP CBK Reference, Fifth Edition, Chapter 5, Identity and Access Management, page 701.
