Which statement correctly distinguishes In-Band from Out-of-Band authentication?

Which statement correctly distinguishes In-Band from Out-of-Band authentication?

• A. In-Band uses a separate channel; Out-of-Band uses the same channel
• B. In-Band relies on a password only; Out-of-Band uses biometric
• C. In-Band relies on the same channel; Out-of-Band uses a separate channel
• D. In-Band uses hardware tokens; Out-of-Band uses software tokens

Answer: (C)

The main idea here is how the channel used to deliver or verify the second factor differs between in-band and out-of-band authentication. In-band authentication completes the verification over the same communication path you used to access the service — everything happens through the same channel. Out-of-band authentication, on the other hand, uses a separate channel, often involving a different device or medium, to deliver or approve the second factor. So, the statement that In-Band relies on the same channel and Out-of-Band uses a separate channel correctly captures this distinction. For example, a code shown or entered within the same login session on the web page would be in-band, while a code sent via SMS to your phone or a push notification to a separate authenticator app would be out-of-band. The other options mix up the idea. Authentication methods aren’t strictly defined by password versus biometrics, nor by hardware versus software tokens; the key difference is whether the second factor travels through a different channel than the initial access path.

The main idea here is how the channel used to deliver or verify the second factor differs between in-band and out-of-band authentication. In-band authentication completes the verification over the same communication path you used to access the service — everything happens through the same channel. Out-of-band authentication, on the other hand, uses a separate channel, often involving a different device or medium, to deliver or approve the second factor.

So, the statement that In-Band relies on the same channel and Out-of-Band uses a separate channel correctly captures this distinction. For example, a code shown or entered within the same login session on the web page would be in-band, while a code sent via SMS to your phone or a push notification to a separate authenticator app would be out-of-band.

The other options mix up the idea. Authentication methods aren’t strictly defined by password versus biometrics, nor by hardware versus software tokens; the key difference is whether the second factor travels through a different channel than the initial access path.