Which best describes two-factor authentication?

Two-factor authentication is best described as a security process that requires two forms of identification. This method significantly enhances security by combining something the user knows (like a password) with something the user has (like a mobile device or security token) or something the user is (biometric data such as a fingerprint). By requiring these two independent pieces of evidence, it effectively reduces the risk of unauthorized access, ensuring that even if one factor, such as a password, is compromised, the account remains protected unless the second factor is also breached.

The other options do not accurately reflect the concept of two-factor authentication. A method that requires only a password does not indicate the use of two forms of identification. A software that enhances password complexity may help in securing passwords but does not implement the principle of multiple factors. Lastly, a network segmentation strategy refers to dividing a network into smaller, manageable sections for security and efficiency, which does not relate to user authentication processes at all. Hence, the definition provided in the correct answer encapsulates the essential elements of two-factor authentication effectively.