問63
頻出度★★★
PC やスマートフォンのブラウザから無線 LAN のアクセスポイントを経由して, インターネット上の Web サーバにアクセスする。このときの通信の暗号化に利用する SSL/TLS と WPA2に関する記述のうち, 適切なものはどれか。
令和3年度 ITパスポート試験 問63
This question's explanation and your answers so far.
解説
問 63
Incorrectア
WPA2 encrypts only the wireless segment between the device and the wireless LAN access point; beyond the access point (all the way to the web server on the internet) it is not protected. Therefore WPA2 alone cannot encrypt the entire communication between the browser and the web server, so this is incorrect.
- イ
正解 SSL/TLS exchanges keys directly between the browser (the client) and the web server, and encrypts the communication itself that flows between the two ends (end-to-end encryption). Regardless of whether the wireless LAN or the various internet segments along the route are encrypted, it can protect the content of the communication between the browser and the web server. Therefore choice イ, which states that “regardless of whether WPA2 is used, by using SSL/TLS you can encrypt the communication between the browser and the web server,” is appropriate.
Incorrectウ
Which encryption method to use is not determined by whether the connecting device is a PC or a smartphone. SSL/TLS covers the section between the browser and the web server, while WPA2 covers the wireless segment; this is a difference in their roles, so the statement that you choose between them by device type is incorrect.
Incorrectエ
As with choice ウ, the premise of choosing the method by device type is wrong. Moreover, even if a PC uses WPA2, it still cannot encrypt the entire communication between the browser and the web server, so it is also inappropriate as an understanding of their roles.
ここがポイント
- WPA2 is a method that encrypts only the wireless LAN segment (between the device and the access point), and its protection is limited to that segment.
- SSL/TLS is a method that encrypts end-to-end between the browser and the web server, and it can protect the communication content without depending on whether wireless encryption exists along the route.
用語