問98
頻出度★★★
A 社では紙の顧客名簿を電子化して, 電子データで顧客管理を行うことにした。 顧客名簿の電子データからの情報漏えいを防ぐ方法として, 適切なものはどれか。
平成30年度 春期 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
A digital signature is a mechanism that guarantees the “integrity (tamper detection)” of data and the “non-repudiation of the author”; the content itself is not encrypted and remains readable as plaintext. It cannot prevent leakage (a breach of confidentiality).
Incorrectイ
Frequent backups are an “availability” measure that lets data be restored in case of failure or accidental deletion. They cannot prevent data from leaking; on the contrary, as the number of copies grows, the paths for leakage may even widen.
Incorrectウ
RAID is an “availability and reliability” technology that makes disks redundant so that data is not lost even when a failure occurs. Since the stored data is not encrypted, if a disk or device is carried off, its content can be read, and leakage cannot be prevented.
- エ
正解 The core of preventing information leakage is ensuring “confidentiality” (Confidentiality), that is, making sure that even if data leaks to the outside, its content cannot be read by a third party. The encryption in choice “エ” converts the electronic customer-list data into a form that cannot be decrypted by anyone without the encryption key, and stores it in that form. As a result, even if the file is stolen, or even the whole USB drive or PC is carried off, the names, addresses, and other contents inside cannot be read without the key, so it directly prevents information leakage. Therefore “エ” is appropriate.
ここがポイント
- Among the three elements of information security, protection against information leakage corresponds to ensuring “confidentiality” (Confidentiality). If data is encrypted before being stored, it cannot be read without the key even if it leaks out.
- Distinguish which security element each measure protects: digital signature = integrity and non-repudiation; backup / RAID = availability.
用語