3.3 Wireless Network

Question 1

What devices can use Wi-Fi?

Answer 1

Laptops, desktops, tablets, smartphones (IoT devices like lights, Tv’s etc.)

Question 2

What devices can use bluetooth?

Answer 2

Wireless headphones, connecting phones to car entertainment systems, keyboards etc.

Question 3

What is bluetooth?

Answer 3

A wireless method of connecting devices together over a short distance

Question 4

Features of bluetooth

Answer 4

• Uses radio waves at 2.4GHz

- Devices are typically 10 metres of each other

Question 5

What is Bluetooth pairing?

Answer 5

• A persistent link is made between the 2 devices
• A device can ask for a passkey in order to pair to it - gives a layer of security like a password
• When a paired device is close enough to communicate it will say that it is connected

Question 6

What are passkeys?

Answer 6

Passkeys only need to be entered once and will be remembered by devices that are paired

Question 7

Wireless transmission

Answer 7

Commonly uses radio waves for communication

Question 8

Why is wireless transmission not reliable?

Answer 8

Susceptible to interference from objects and other nearby electronic or radio devices

Question 9

Wireless NICs

Answer 9

Built into every networked device capable of connecting to a wireless network

Question 10

Examples of devices that use NIC’s

Answer 10

• PCs
• Smart Phones
• Wireless speakers

Question 11

WAP (Wireless access point)

Answer 11

A device that allows wireless devices to connect to a wired network using Wi-Fi
The AP usually connects to a router via a wired network

Question 12

802.11 types

Answer 12

802. 11b/g/n uses 2.4GHz frequency

802. 11a/n/ac uses 5GHz frequency

Question 13

802.11b/g/n uses 2.4GHz frequency Advantages and Disadvantages

Answer 13

• Greater range and coverage

- More interference from other devices as this is a crowded frequency

Question 14

802.11a/n/ac uses 5GHz frequency Advantages and Disadvantages

Answer 14

• Less crowded space with 23 non-overlapping channels with higher data transmission rates
• Less able to penetrate through walls

Question 15

What is intercepting data

Answer 15

Any intercepted data can be read and understood unless the data is encrypted

Question 16

What is encryption?

Answer 16

Encryption is the encoding of data so that it can no longer be easily understood by a shift cipher

Question 17

Plaintext

Answer 17

Original message to be encrypted

Question 18

Ciphertext

Answer 18

The encrypted message

Question 19

Encryption

Answer 19

The process of converting plaintext into ciphertext

Question 20

Key

Answer 20

A sequence of numbers use to encrypt or decrypt, often data using a mathematical formula

Question 21

Encryption algorithm

Answer 21

The formula for encrypting the plaintext

Question 22

What are the 2 inputs for encryption?

Answer 22

Plaintext and a secret key

Question 23

Encryption techniques

Answer 23

Private key (Symmetric encryption)
Public key (Asymmetric encryption)

Question 24

What is private key?

Answer 24

A single key is used to encrypt and decrypt a message and must be given to the recipient of your message to decrypt the data

Question 25

What is a public key?

Answer 25

2 keys are used - one (public key) to encrypt and the other (private key) to decrypt data
This is more secure as it means that you never have to send or reveal your decryption key

Question 26

What is the Caesar Shift Cipher?

Answer 26

Earliest substitution cipher where each letter is replaced by a a letter n positions further on in the alphabet (symmetric encryption)q

Question 27

What methods of encryption are used when using wireless networks?

Answer 27

Most common wireless security standards are WEP (Wired Equivalent Privacy) and WPA (Wi-Fi Protected Access)

Question 28

Why should you use WPA or WPA2 encryption methods?

Answer 28

The WEP method of encryption is older and can be cracked in seconds

Question 29

Why is HTTPS recommended for websites?

Answer 29

It encrypts data sent to and received from the site

Question 30

Strong encryption

Answer 30

When the useful lifetime of the encrypted data is less than the time taken to break the code

Question 31

Weak encryption

Answer 31

Code may be broken in time to use the information, but a lot of effort is required it might not be worth it

Question 32

How you could use wireless networks and network security in your life?

Answer 32

We use a wireless router at home. This contains a switch, route and modem all in one box. All our mobile devices connect to the WAP with Wi-Fi. It is encrypted with WPA2. We don’t use WEP as it is insecure. Where possible we try to connect to websites with HTTPS as this makes all data transmitted secure. Our TV and soundbar are connected to the box using Ethernet cables. Bluetooth is used to connect our headphones to smartphones