問84
頻出度★★★
システムで利用するハードディスクを RAID のミラーリング構成にすることによって, 高めることができる情報セキュリティの要素はどれか。
平成26年度 春期 ITパスポート試験 問84
テクノロジ系セキュリティ › 情報セキュリティ管理
This question's explanation and your answers so far.
解説
問 84
- ア
正解 The correct answer is ア “Availability.” RAID mirroring (RAID 1) is a configuration that writes the same data to two or more hard disks at the same time, keeping duplicate copies. Because of this, even if one disk fails physically, the other disk still holds the same data, so the system can keep processing without stopping, and once the failed disk is replaced the original duplicated state can be restored. In other words, a failure of a single disk no longer leads directly to a system outage or to data loss. Among the three elements of information security (confidentiality, integrity, availability), availability means ensuring a state in which authorized users can use information and information systems whenever they need them, and mirroring, which reduces the downtime caused by a disk failure, is exactly a measure that improves availability. Note as well that mirroring is a safeguard against hardware failure: data altered or deleted by a mistaken operation or by a virus is written to both disks at once, so mirroring is not a substitute for backups.
Incorrectイ
Confidentiality means that only authorized people can access information, and it is raised by measures such as encryption, access-permission settings, and user authentication. Mirroring merely places another copy of the same data on a second disk; it does not narrow the range of people who can access that data. If anything, as copies increase, the paths for leakage through theft or removal of a disk may also increase, so it cannot be called a measure that improves confidentiality.
Incorrectウ
Authenticity is the property that a user or a piece of information can be confirmed to be genuine (that is, not an impersonation), and it is secured by user authentication, digital signatures, and the like. Mirroring is nothing more than a storage-redundancy technique that duplicates writes to disks; it has no function for verifying whether the other party is really who they claim to be, or whether data came from a legitimate sender.
Incorrectエ
Accountability is the property that it can later be traced and identified who did what and when, and it is secured by collecting and preserving access logs and operation histories. Mirroring has no mechanism for recording or auditing logs, and duplicating the data does not make it possible to identify what a user did, so this choice is wrong.
ここがポイント
- Among the three elements of information security, availability means being able to use information and systems whenever they are needed. Redundancy and fault countermeasures such as RAID mirroring (RAID 1), redundant power supplies, cluster configurations, and recovery from backups all improve availability.
- Confidentiality relies on encryption and access control, integrity on tamper detection and hashes, authenticity on authentication and digital signatures, and accountability on collecting and preserving logs. Memorizing these element-to-countermeasure pairings lets you tell the choices apart.
用語