An authenticator app displays a number that changes at regular intervals during console login.
Which description is appropriate?
An OTP is a passcode valid once or for a short period, reducing the value of a captured code.
Detailed explanation
Incorrect. A permanently shared fixed password is the opposite of an OTP.
Incorrect. A permanently shared fixed password is the opposite of an OTP.
Incorrect. An OTP is not itself a public-key file.
Incorrect. An OTP is not itself a public-key file.
Incorrect. A firewall port number is unrelated to an authentication code.
Incorrect. A firewall port number is unrelated to an authentication code.
Correct. A one-time password is intended for one use or a short validity window.
Correct. A one-time password is intended for one use or a short validity window.
Try it yourself
An example you can run in a temporary verification environment.
printf '%s\n' 'one-time or short-lived authentication code'Expected result
one-time or short-lived authentication codeKey points
- OTP
- Short validity
- Replay prevention
Notes
- Environment: 多要素認証の概念確認
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.