OCR J277 Topic 1.3.2

Wired, Wireless & Encryption

How devices physically connect and how we keep that data safe.

Learning Checklist

Your Progress:
0/4
Click to view full objective list
1

Wired vs. Wireless Connections

To send data across a network, devices need a physical medium. This is either done through physical cables or through the air using radio waves.

Wired (Ethernet)

Uses physical copper cables or fibre optics to connect devices. Ethernet is the standard protocol for wired LANs.

High Bandwidth: Very fast data transfer speeds.
Reliable: Doesn't suffer from signal interference (e.g., walls won't block it).
Secure: To intercept data, a hacker must physically plug into the cable.
Not Portable: You are tethered to the wall. Cables can be trip hazards.

Wireless (Wi-Fi & Bluetooth)

Uses radio waves to transmit data. Wi-Fi connects you to a network, whilst Bluetooth pairs devices together over short distances.

Portable: Users can move around freely while staying connected.
Easy to Add Devices: No need to drill holes or run new cables.
Interference: Signals can be blocked by thick walls or disrupted by microwaves.
Less Secure: Data is broadcast through the air; anyone nearby could intercept it.
2

Choosing the Right Connection

Exam Trap: Be Specific!

In the exam, don't just say "it is faster" or "it is better". Use specific terminology! Say "it has higher bandwidth" or "it provides greater portability". Always justify your choice based on the scenario given.

Test yourself: Read the scenarios below and think of your answer before clicking to reveal the correct recommendation and justification.

Scenario A: A desktop PC in a bank processing sensitive financial transactions.
Reveal Answer

Recommendation: Wired (Ethernet).

Justification: Ethernet provides the highest level of security, reducing the risk of unauthorised interception. The desktop PC does not need to move, so portability is not required.

Scenario B: A customer using a smartphone in a cafe.
Reveal Answer

Recommendation: Wireless (Wi-Fi).

Justification: Smartphones do not typically have Ethernet ports. Wi-Fi allows the customer the portability to move around the cafe while browsing the internet.

Scenario C: Connecting a smartwatch to a mobile phone.
Reveal Answer

Recommendation: Wireless (Bluetooth).

Justification: Bluetooth is ideal for connecting personal devices over very short distances without needing a router or trailing wires.

3

The Principle of Encryption

Because wireless signals are broadcast through the air, anyone with a receiver in range can "listen in" and intercept the data. To stop hackers reading your private messages or stealing passwords, we use Encryption.

What is Encryption?

Encryption is the process of scrambling data into an unreadable format before it is transmitted across a network.

  • The original, readable data is called Plaintext (e.g., "HELLO").
  • An algorithm and a secret Key are used to scramble the data.
  • The scrambled, unreadable data is called Ciphertext (e.g., "X8F9Q").
  • When the Ciphertext reaches its destination, the receiving computer uses the Key to decrypt it back into Plaintext.
Crucial point for exams: Encryption does not stop data from being intercepted! It simply means that if the data is intercepted, it is completely meaningless to the hacker without the key.

Key Vocabulary

Bandwidth: The maximum amount of data that can be sent across a connection at once.
Interference: When signals are blocked or degraded by physical objects or other electronic waves.
Ciphertext: Data that has been scrambled using encryption and cannot be read.
Interception: When data is secretly captured by a third party while travelling across a network.

Lesson Summary & Review

Make sure all items are checked off before moving on to Lesson 2: IP and MAC Addressing.