Two-factor authentication in Intro to Computing - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the main purpose of two-factor authentication?

Imagine you have a safe that requires two different keys to open. What is the main reason for using two keys instead of just one?

A To increase security by requiring two different proofs of identity

B To allow more people to open the safe at the same time

C To make it easier to open the safe quickly

D To reduce the cost of making keys

💡 Hint

Think about how having two locks instead of one affects safety.

Two-factor authentication requires two different types of proof to confirm identity, making unauthorized access much harder.

❓ trace

intermediate

Trace the steps in a two-factor authentication process

Follow the steps below and identify what happens after the user enters their password correctly.

1. User enters username and password.
2. System checks password.
3. ?
4. User enters code from their phone.
5. System verifies code and grants access.

A System resets the user's password.

B System asks for a security question answer.

C System logs the user out immediately.

D System sends a code to the user's phone.

💡 Hint

Think about what the second factor usually is in two-factor authentication.

After verifying the password, the system sends a code to the user's phone as the second factor.

❓ Comparison

advanced

Compare single-factor and two-factor authentication

Which of the following best explains the difference between single-factor and two-factor authentication?

A Single-factor requires only one proof of identity; two-factor requires two different proofs.

B Single-factor uses two passwords; two-factor uses one password and one code.

C Single-factor is more secure than two-factor authentication.

D Two-factor authentication does not require a password.

💡 Hint

Think about how many types of identity proof each method requires.

Single-factor authentication uses one proof (like a password), while two-factor requires two different proofs (like password + code).

❓ identification

advanced

Identify the second factor in two-factor authentication

Which of the following is commonly used as the second factor in two-factor authentication?

A Email address

B Password

C Fingerprint or code sent to phone

D Username

💡 Hint

The second factor is usually something you have or something you are.

The second factor is often a fingerprint (something you are) or a code sent to your phone (something you have).

🚀 Application

expert

What happens if the second factor code is entered incorrectly multiple times?

Consider a system that locks the user out after three wrong two-factor codes. What is the main reason for this behavior?

A To allow the user to try unlimited times without risk

B To prevent unauthorized access by blocking repeated guessing

C To reset the user's password automatically

D To send the correct code to the user again

💡 Hint

Think about how repeated wrong attempts can be a security risk.

Locking out after multiple wrong attempts stops attackers from guessing codes repeatedly.