問55
頻出度★★★
ブラウザとWebサーバ間でSSLを使った通信を行うことを示すURLの先頭の記述として, 適切なものはどれか。
平成27年度 春期 ITパスポート試験 問55
This question's explanation and your answers so far.
解説
問 55
Incorrectア
http:// is the scheme that indicates ordinary HTTP communication without encryption. Because the content travels as plain text, it can be eavesdropped on or tampered with along the way, so it cannot indicate communication that uses SSL.
- イ
正解 The method of carrying out HTTP communication with SSL/TLS encryption is called HTTPS (HTTP over SSL/TLS), and the scheme part of its URL is written as https://. If the browser address bar starts with https://, it means that the communication between the browser and the Web server is encrypted with SSL/TLS, and that the server certificate has also confirmed that the party you are connecting to is genuine. This notation is used where eavesdropping, tampering, and spoofing must be prevented, such as payment screens and login screens of online shopping sites. Therefore the correct answer is イ, https://.
Incorrectウ
shttp:// is not a notation used on today's Web to indicate SSL communication. The standard scheme that represents HTTP protected by SSL/TLS is only https, and shttp:// is never used at the beginning of a URL in a browser.
Incorrectエ
There is no scheme called ssl:// in the standard notation for URLs. SSL/TLS is only a lower-layer mechanism that encrypts higher-layer protocols such as HTTP, and as a URL scheme it is expressed by the protocol name https.
ここがポイント
- HTTPS = HTTP + SSL/TLS. If a URL begins with https://, the communication between the browser and the Web server is encrypted, and server authentication by a server certificate is also performed.
- The beginning of a URL (the scheme) indicates the communication method used. Remember that http:// means no encryption and https:// means SSL/TLS is used, and keep in mind that notations such as shttp:// and ssl:// are not used.
用語