What Is Two-Factor Authentication (2FA)?

Two-factor authentication (2FA) is a second layer of security to protect an account or system. Users must go through two layers of security before being granted access to an account or system. 2FA increases the safety of online accounts by requiring two types of information from the user, such as a password or PIN, an email account, an ATM card or fingerprint, before the user can log in. The first factor is the password; the second factor is the additional item.

Understanding Two-Factor Authentication (2FA)

2FA is designed to prevent unauthorized users from gaining access to an account with nothing more than a stolen password. Users may be at greater risk of compromised passwords than they realize, particularly if they use the same password on more than one website. Downloading software and clicking on links in emails can also expose an individual to password theft.

Despite the slight inconvenience of a longer log-in process, security experts recommend enabling 2FA wherever possible: email accounts, password managers, social media applications, cloud storage services, financial services, blogging platforms and more. Apple account holders, for example, can use 2FA to ensure that accounts can only be accessed from trusted devices. If a user tries to log in to their iCloud account from a different computer, the user will need the password, but also a multi-digit code that Apple will send to one of the user's devices, such as their iPhone.

2FA is not just applied to online contexts. 2FA is also at work when a consumer is required to enter their zip code before using their credit card at a gas pump or when a user is required to enter an authentication code from an RSA SecurID key fob to log in remotely to an employer’s system.

While 2FA does improve security, it is not foolproof. Hackers who acquire the authentication factors can still gain unauthorized access to accounts. Common ways to do so include phishing attacks, account recovery procedures and malware. Hackers can also intercept text messages used in 2FA. Critics argue that text messages are not a true form of 2FA since they are not something the user already has but rather something the user is sent, and the sending process is vulnerable. Instead, the critics argue that this process should be called two-step verification. Some companies, such as Google, use this term. Still, even two-step verification is more secure than password protection alone. Even stronger is multi-factor authentication, which requires more than two factors before account access will be granted.