Which technology can help prevent unauthorized access to accounts?

Two-factor authentication is a security measure that significantly enhances account protection by requiring two distinct forms of verification before granting access. This typically involves something the user knows, such as a password, along with something the user has, like a mobile device that receives a text message or an authenticator app. This layered approach ensures that even if someone obtains the password, they would still need the second factor to gain access to the account, thereby preventing unauthorized access.

In contrast, relying solely on usernames and passwords can be insufficient for security because passwords can be weak, reused, or stolen through various means such as phishing attacks. IP address filtering, while offering some level of security, can be bypassed since users often access accounts from different locations or devices. Cookie tracking does not prevent unauthorized access but rather tracks user behavior on websites and is primarily used for analytics and personalized experiences. Thus, two-factor authentication stands out as the most effective measure for preventing unauthorized account access.