問58
頻出度★★★
テザリングの説明として, 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58
テクノロジ系ネットワーク › ネットワーク応用
This question's explanation and your answers so far.
解説
問 58
Incorrectア
A type of virus that self-replicates and spreads its infection via networks and other channels describes a worm. A worm does not attach itself to other programs; it multiplies on its own and spreads over networks, and it is malware — a completely different concept from tethering, which shares a communication line.
- イ
正解 The correct answer is イ. Tethering means using a communication terminal that has a mobile line (4G/5G), such as a smartphone or tablet, as a relay device like a mobile router, so that devices with no line of their own — PCs, game consoles and so on — can connect to the Internet. As the word tether (a rope for tying something) suggests, the image is that other devices are tied to the terminal and share its line. There are three connection methods: Wi-Fi tethering, Bluetooth tethering, and USB tethering (connecting with a USB cable). Wi-Fi is the easiest and suits connecting several devices, Bluetooth uses little power, and USB is stable and lets you charge the phone while using it. The benefit is that you can get a PC online even when you are out and there is no public wireless LAN; on the other hand, the traffic consumes the data allowance of the mobile plan on the phone, so you must watch out for speed throttling after exceeding the data cap. Choice イ describes exactly this feature, so it is appropriate.
Incorrectウ
A method that detects tampering of electronic data by using a hash function and public-key cryptography describes a digital signature (electronic signature). The sender encrypts a hash value with a private key and the receiver verifies it with the public key, which achieves tamper detection and identification of the sender. It is not a feature for sharing an Internet connection.
Incorrectエ
An attack that illegally manipulates information inside a database by deliberately entering SQL commands into the input fields of a web page describes SQL injection. It is an attack technique that exploits inadequate validation of input values in a web application, and it has nothing to do with tethering.
ここがポイント
- Tethering = a feature that uses a communication terminal such as a smartphone as a substitute for a mobile router so that devices like PCs can connect to the Internet. There are three connection methods: Wi-Fi, Bluetooth, and USB.
- In questions that ask you to tell IT loanword terms apart, learning the terms the other choices point to as well (worm, digital signature, SQL injection) lets you reach the correct answer reliably by elimination.
用語