令和5年度 ITパスポート試験問65

This question's explanation and your answers so far.

問65

頻出度★★★

Wi-Fi のセキュリティ規格である WPA2を用いて, PC を無線 LAN ルータと接続するときに設定する PSK の説明として, 適切なものはどれか。

出典　令和5年度 ITパスポート試験問65

解説

問 65

ア
正解 PSK (Pre-Shared Key) is a common code (passphrase) configured in advance on both sides when connecting a PC to a wireless LAN router (access point) in WPA2 Personal mode. At connection time, this PSK is used to authenticate whether the other party is the correct destination, and based on the PSK, through a procedure called the 4-way handshake, an encryption key for securing communication is dynamically generated for each connected PC. Therefore, choice ア, which describes it as a passphrase used for authentication from which a per-PC encryption key is generated, is correct.
Incorrectイ
The first half, a passphrase used for authentication, is a correct description of the PSK, but the PSK's role is authentication and encryption-key generation, not IP address assignment. Assigning a private IP address to each PC is a function of DHCP and has nothing to do with the PSK, so it is incorrect.
Incorrectウ
A name used to identify the access point to connect to describes not the PSK but the SSID (network identifier name). The latter half about encryption-key generation is correct, but its underlying subject has been switched from the PSK to the SSID, so as a description of the PSK it is incorrect.
Incorrectエ
The first half, a name that identifies the access point, describes the SSID, not the PSK, and the second half, IP address assignment, is a function of DHCP. Since neither the identifier name nor IP assignment is the PSK's role, it is wrong on two counts.

ここがポイント

The PSK (Pre-Shared Key) is a shared passphrase configured in WPA2 Personal; it is used for connection authentication and at the same time serves as the basis for generating a per-PC communication encryption key.
The name that identifies an access point is the SSID, and assigning a private IP address to each PC is the role of DHCP; both should be distinguished as concepts separate from the PSK.

用語

解答問65ア