問69
頻出度★★★
無線 LAN の暗号化方式である WEP は, 暗号が容易に解読されてしまうという問題が指摘されている。WEP の弱点を改善し, 暗号強度を高めた暗号化方式はどれか。
平成29年度 秋期 ITパスポート試験 問69
テクノロジ系ネットワーク › ネットワーク方式
This question's explanation and your answers so far.
解説
問 69
Incorrectア
ESSID is a network name (identifier) used to identify a wireless LAN access point; it is not an encryption method. It is not a mechanism that encrypts communication content, so it cannot be a successor to WEP.
Incorrectイ
S/MIME is a method for encrypting and digitally signing the body and attachments of email; its target is email and it has nothing to do with encrypting the wireless LAN communication segment. It is not an improvement on WEP.
Incorrectウ
SSL (and its successor TLS) encrypts communication such as that between a web browser and a server at a level closer to the application layer, and is used in HTTPS and the like. It is not a successor to WEP, the encryption standard for the wireless LAN link segment.
- エ
正解 The answer is WPA2 (エ). Wireless LAN encryption standards have evolved in the order WEP → WPA → WPA2. Early WEP had a weakness: because of key reuse and a fragile encryption algorithm (its use of RC4), an intercepted communication could have its key cracked in a short time. WPA improved on this weakness, and WPA2 further raised the encryption strength by adopting AES as its encryption algorithm. Therefore, the wireless LAN encryption method that improves on WEP’s weaknesses and increases encryption strength is WPA2.
ここがポイント
- Wireless LAN encryption standards have been strengthened in the order WEP → WPA → WPA2. WEP has a weakness of being easily cracked, while WPA2 is a successor standard that adopts AES as its encryption algorithm to increase encryption strength.
- Distinguish clearly that ESSID (a network identifier), S/MIME (email encryption), and SSL/TLS (encryption for upper-layer communication such as the web) are none of them successor standards to WEP, which encrypts the wireless LAN link segment.
用語