問75
頻出度★★★
情報セキュリティの機密性を直接的に高めることになるものはどれか。
平成25年度 秋期 ITパスポート試験 問75
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 75
Incorrectア
Obtaining operation logs at the end of the day's work and confirming that there is no trace of leakage is a detective control, meant to find misconduct after the fact. It is important as an audit trail, but at the moment of checking a leak may already have occurred, and it can neither prevent the leak itself nor make the leaked contents unreadable. It only helps indirectly in maintaining confidentiality, so it cannot be called a measure that directly enhances it.
Incorrectイ
Checking whether the date of the previous access is correct when accessing the file is an after-the-fact check, intended to make users themselves notice accesses they do not remember making, that is, signs of unauthorized use. This too is a detective control, and it has no power to block unauthorized access or to protect the contents of the information. Therefore it does not directly enhance confidentiality.
Incorrectウ
Making backups so that information can be restored after destruction or tampering is a measure that enhances availability (keeping information usable when it is needed) and integrity (keeping information accurate and complete). On the contrary, as backup media increase, poor management can even create additional leakage routes, so this is not a measure that directly enhances confidentiality.
- エ
正解 The correct answer is エ. Among the three elements of information security, confidentiality means keeping information in a state where only authorized people can view it and unauthorized people cannot learn its contents. If a confidential information file is encrypted in advance, then even if the file leaks outside the organization, a third party without the decryption key cannot decipher its contents. In other words, this measure technically and directly realizes the very definition of confidentiality: not letting unauthorized people know the contents. The other options are indirect, after-the-fact measures such as checking later whether a leak occurred, or restoring damaged data to its original state. Only encryption protects the contents of the information itself and directly enhances confidentiality.
ここがポイント
- The three elements of information security: confidentiality (only authorized people can access the information), integrity (the information is accurate and has not been tampered with), and availability (the information can be used when it is needed). A classic exam pattern is to ask which element a given measure works on: encryption and access-right settings correspond to confidentiality, digital signatures and hashes to integrity, and backups and redundancy to availability.
- How to judge whether something directly enhances confidentiality: distinguish preventive controls that protect the information itself, such as encryption, from detective controls that find anomalies after the fact, such as checking logs or reviewing access records. Detective controls are effective measures, but note that they do not directly enhance confidentiality.
用語