Which additional security factor is recommended alongside smart card authentication?

Smart card authentication provides a robust method for verifying user identities by storing credentials securely on a physical card. However, to enhance security further, it is recommended to use an additional factor, which is where biometric data comes into play. Biometric authentication relies on unique physical characteristics of an individual, such as fingerprints, iris patterns, or facial recognition. This factor significantly strengthens the security posture because it is something inherent to the user and cannot be easily replicated or stolen, unlike passwords or tokens.

Incorporating biometric data alongside smart card authentication ensures that two different modalities are being used: something the user has (the smart card) and something the user is (biometric information). This dual-factor approach makes unauthorized access much more difficult, as a potential attacker would need both the physical card and the biological trait.

In contrast, other options like password complexity and security questions can be more easily compromised through social engineering or brute force attacks. Token-based authentication, while useful, does not combine the same level of unique personal verification that biometrics provide. Thus, using biometric data as a complementary security measure with smart card authentication is a highly effective strategy to enhance overall security.