問57
頻出度★★★
SSL/TLS による通信内容の暗号化を実現させるために用いるものはどれか。
平成30年度 春期 ITパスポート試験 問57
This question's explanation and your answers so far.
解説
問 57
Incorrectア
ESSID (SSID) is merely a network name that identifies a wireless LAN access point; it is not a mechanism for encrypting communication content and is unrelated to SSL/TLS encryption.
Incorrectイ
WPA2 is a security standard that encrypts the wireless LAN segment (Wi-Fi); it is used to protect the wireless segment, but it is not the element that achieves SSL/TLS encryption, which protects web communication and the like all the way from the device to the server.
- ウ
正解 With SSL/TLS, at the very start of communication (the handshake) the server first presents a “server certificate.” This certificate contains the server’s public key and the signature of a certificate authority (CA); the client uses it to confirm that the other party is the correct server, and then uses the public key to safely hand over a shared (common) key. From then on that shared key is used to encrypt the communication content, so the item used to achieve the encryption is the “server certificate,” which is ウ.
Incorrectエ
A firewall is a mechanism that performs access control by allowing or blocking communication; it does not encrypt the data passing through it, so its role differs from SSL/TLS encryption.
ここがポイント
- In the handshake, SSL/TLS uses a server certificate (a digital certificate containing a public key) to perform server authentication and key exchange, then encrypts the communication content with a shared key.
- Distinguish the roles of each term: ESSID = the identifier name of a wireless LAN, WPA2 = the encryption standard for a wireless LAN, and firewall = access control.
用語