問65
頻出度★★★
認証局 (CA:Certificate Authority) は, 公開鍵の持ち主が間違いなく本人であることを確認する手段を提供する。この確認に使用されるものはどれか。
平成29年度 春期 ITパスポート試験 問65
This question's explanation and your answers so far.
解説
問 65
Incorrectア
Digital signage is a mechanism that displays advertisements or guidance using electronic display media such as screens; it has nothing to do with public keys or identity verification. It is a term from a completely different field than the functions of a certificate authority.
Incorrectイ
Digital forensics is an investigative technique for collecting, preserving, and analyzing data that serves as evidence after incidents such as unauthorized access or information leakage. It is not a means to confirm whether the owner of a public key is the genuine person.
- ウ
正解 The correct answer is “ウ: Digital certificate.” A certificate authority (CA) binds a public key to the identity information of its owner (an organization or an individual) and issues a digital certificate that carries the CA’s own digital signature. By verifying this certificate, a user can confirm that the public key they received truly belongs to the party it claims to come from. In other words, the very means that guarantees that “the owner of a public key is indeed the genuine person” is the digital certificate, and the CA is the trusted third-party organization responsible for issuing and managing it.
Incorrectエ
Biometric authentication is a method that authenticates an individual using physical characteristics such as fingerprints, face, or iris. Although it is one method of personal authentication, it is not something that a CA issues to prove the owner of a public key. What a CA provides is a digital certificate.
ここがポイント
- A certificate authority (CA) is a trusted third-party organization that binds a public key to its owner’s identity and issues a digital certificate signed with its own digital signature.
- In public-key cryptography, guaranteeing “whether the received public key truly belongs to the person” is the role of the digital certificate, and this forms the core of the public-key infrastructure (PKI).
用語