問98
頻出度★★★
アンチパスバック方式はIDの状態を記録し, 入室済みのIDでの再入室, 退室済みのIDでの再退室を規制するものである。IDカードを用いた入退室管理システムを導入した部屋の利用制限について, アンチパスバック方式を導入することで実現できることはどれか。
平成28年度 秋期 ITパスポート試験 問98
This question's explanation and your answers so far.
解説
問 98
Incorrectア
Setting an upper limit on the number of entries and exits within a fixed period and stopping entry once it is exceeded is a different method that counts and limits the number of times. Anti-passback only tracks the consistency of the state of whether an ID is inside or outside the room and does not manage any count limit, so this cannot be achieved.
- イ
正解 The anti-passback method records the two states “entered” and “exited” for each ID, and restricts re-entry with an ID already in the “entered” state and re-exit with an ID already in the “exited” state. In option イ, the person tailgates in alongside another person’s entry without having their own ID card read, so the system cannot update that ID to “entered” and it stays in the “exited” (outside the room) state. Afterward, when the person tries to exit with their own ID card, the system regards it as a “re-exit with an ID already in the exited state” and refuses. In this way an unauthorized tailgating entry can be detected and restricted at the time of exit, so イ is correct.
Incorrectウ
Anti-passback looks only at the state of whether an ID is “entered” or “exited” and does not judge whether the cardholder is the person themselves or whether they have come to work. As long as a borrowed ID card is in the “outside the room” state, it will be allowed through as a legitimate entry. This is not a personal-authentication mechanism, so it cannot be achieved.
Incorrectエ
Making exit impossible after a fixed amount of time has passed since entry is a restriction on the length of stay, a different kind of control that uses the passage of time as its condition. Anti-passback restricts only the transitions of an ID’s entry/exit state, not the passage of time, so this cannot be achieved.
ここがポイント
- Definition of the anti-passback method: it records the entry/exit state of each ID and forbids re-entry with an already-entered ID and re-exit with an already-exited ID. Therefore a tailgating entry made without having the ID read can be detected and restricted at exit as a “re-exit with an already-exited ID”.
- Anti-passback is a mechanism that ensures the consistency of states; distinguish it from limiting the number of entries/exits, limiting the length of stay, and personal authentication, which differ from it in both purpose and the information they judge on.
用語