Which authentication method utilizes a physical device or software to generate secure, unique codes?

The choice of security keys is a valid one when discussing authentication methods that utilize a physical device or software to generate secure, unique codes. Security keys, which can be physical devices or software-based solutions, are designed to authenticate users by providing an extra layer of security beyond traditional password methods. They generate one-time codes that are used alongside usernames and passwords to ensure that only authorized users have access.

Security keys work in conjunction with two-factor authentication (2FA) or multi-factor authentication (MFA) systems, adding another layer of security by requiring a user to possess the key to gain access. This method mitigates the risks of password theft or phishing attacks, as possession of the security key is required for successful authentication.

The other options may involve elements of authentication but do not fit the criteria as neatly. Hard authentication tokens refer specifically to physical devices that generate codes but may not cover all aspects that security keys account for. Biometric authentication relies on unique biological characteristics rather than codes, and soft authentication tokens typically reference software applications that generate codes, similar to hard tokens but without a physical counterpart, making them less secure in specific contexts.