CompTIA Network+ Practice Test

The TOTP (Time-based One-Time Password) algorithm generates security codes by utilizing a secret key combined with the current time, formatted in a specific way. This method ensures that the codes are unique and time-sensitive. The core idea is that TOTP takes a shared secret key, which is known only to the server and the user's client, and combines it with the current timestamp (typically in 30-second intervals).

This combination of the secret key and the time factor is processed through an HMAC (Hash-based Message Authentication Code) function, which produces a hash that is then truncated to create the final one-time password. Because the time component changes regularly, the generated code is time-limited, so even if someone intercepts a code, they cannot use it after the time period has elapsed.

This mechanism enhances security by ensuring that each code is only valid for a brief window, and since the secret key does not change dynamically (it remains constant), it's the time factor that provides the variation needed for unique codes at each interval.