問69
頻出度★★★
システムの利用者を認証するための方式に関する記述のうち, 適切なものはどれか。
平成30年度 秋期 ITパスポート試験 問69
This question's explanation and your answers so far.
解説
問 69
Incorrectア
“A method that authenticates using a password that can be used only once (a disposable password)” is the description of a one-time password. Single sign-on (SSO) refers to a mechanism that lets a user access multiple servers and applications with a single authentication, so the description and the name do not correspond.
Incorrectイ
“A method that lets a user access multiple authorized servers and applications with a single authentication” is the description of single sign-on (SSO). A one-time password refers to a method that uses a different disposable password each time, so the description and the name are matched the wrong way around.
- ウ
正解 The correct answer is ウ. Matrix authentication is a method in which numbers or characters arranged in a grid (a table) are displayed on the screen, and the user reads off the digits or characters located at the positions matching a “pattern of positions (cells)” memorized in advance, then enters them as the password. Because the displayed numbers change randomly each time, what the user must remember is not the arranged values themselves but only the pattern of “which positions to choose.” Since the entered string is different every time, it has the advantage that even if it is observed by others (shoulder hacking), it is not easily reused as-is the next time. The description in choice ウ accurately explains this mechanism, and the name “matrix authentication” is also correct.
Incorrectエ
“A method that authenticates a person using physical features such as fingerprints or voiceprints” is the description of biometric authentication. Challenge-response authentication is a method in which the user side combines a random number (the challenge) sent from the server with a password or the like, computes a result, and returns that result (the response), thereby authenticating without transmitting the password itself; so the description and the name do not correspond.
ここがポイント
- Correctly distinguish how each authentication method's name maps to its mechanism: one-time password (a disposable, single-use password), single sign-on (a single authentication grants access to multiple systems), matrix authentication (entering the memorized pattern of positions in a table), biometric authentication (physical features such as fingerprints or voiceprints), and challenge-response authentication (authenticating with a random number without transmitting the password).
- Grasp the idea that in matrix authentication the secret is not the values themselves but the “pattern of positions,” and because the entered string changes every time, it works as a countermeasure against peeking.
用語