Interception of data on a network

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Quick Questions

Shade in the A or B circle for each question.

1. Data sent from your laptop to a website travels directly, so no other device ever handles it.

A False: data passes through routers and other devices on the way

B True: data goes straight from sender to receiver

2. What is an eavesdropper doing when they intercept data on a network?

A Deleting the packets so they never arrive

B Copying packets as they travel across the network

3. A hacker captures unprotected data sent across a network. What can they do with it?

A Read it, because it is not protected

B Nothing, because data in transit cannot be read

4. Which place is the bigger risk for interception?

A A private home network with a strong password

B Public Wi-Fi in a cafe

5. Intercepting data means the eavesdropper must break into the sender's computer.

A False: they copy data while it is travelling across the network

B True: they must take control of the sender's device

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1interception		AUnprotected data can be read by anyone who intercepts it. Only protection such as encryption makes it unreadable.
2eavesdropper = copy(packets)		BSomeone copies data as it travels across a network, so unprotected data can be read by them
3Data crosses routers and other devices on its journey, so any of them could be used to copy it		CAn eavesdropper captures and copies packets as they pass through a router on their way to the receiver
4Public Wi-Fi is risky because anyone connected to the network can intercept unprotected data		DData does not travel directly. It passes through routers and other devices, where it can be intercepted and copied.
5Data goes straight from sender to receiver, so nobody else can see it		Esender -> router -> router -> receiver
6Intercepted data cannot be read, even when it is not protected		Fwifi = 'Free_Cafe_WiFi'; send(password)

Definitions

interception

Fill in the Blanks

Complete each line of code by filling in the missing parts.

IF network = "public" THEN OUTPUT "Risk of interception" _____

encrypted ← FALSE readable ← ___ encrypted

packet ← "data" ______ "Eavesdropper copied the packet"

network _ "public Wi-Fi" OUTPUT network

IF public = TRUE ___ secure = FALSE THEN OUTPUT "Anyone can read it" ENDIF

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A packet ← 'password123'

B SEND packet TO router1

C router1 CANNOT COPY packet

Question 2

A network ← 'public Wi-Fi'

B OUTPUT 'Others can connect'

C OUTPUT 'Data is private'

Question 3

A data ← 'bank details'

B encrypted ← FALSE

C SEND data ACROSS network

D interceptorCanRead ← FALSE

Question 4

A path ← [router1, router2]

B FOR EACH device IN packet

C device FORWARDS packet

D NEXT device

Question 5

A wifi ← 'public'

B users ← 'only trusted people'

C risk ← 'interception'

Answer Key

Interception of data on a network

Section A: Quick Questions

A — False: data passes through routers and other devices on the way

B — Copying packets as they travel across the network

A — Read it, because it is not protected

B — Public Wi-Fi in a cafe

A — False: they copy data while it is travelling across the network

Section B: Match the Pairs

interception → Someone copies data as it travels across a network, so unprotected data can be read by them

eavesdropper = copy(packets) → An eavesdropper captures and copies packets as they pass through a router on their way to the receiver

Data crosses routers and other devices on its journey, so any of them could be used to copy it → sender -> router -> router -> receiver

Public Wi-Fi is risky because anyone connected to the network can intercept unprotected data → wifi = 'Free_Cafe_WiFi'; send(password)

Data goes straight from sender to receiver, so nobody else can see it → Data does not travel directly. It passes through routers and other devices, where it can be intercepted and copied.

Intercepted data cannot be read, even when it is not protected → Unprotected data can be read by anyone who intercepts it. Only protection such as encryption makes it unreadable.

Section C: Definitions

interception — When someone copies data as it travels across a network through routers and other devices, so unprotected data can be read by anyone who intercepts it, for example on public Wi-Fi.

Section D: Fill in the Blanks

IF network = "public" THEN
   OUTPUT "Risk of interception"
ENDIF

encrypted ← FALSE
readable ← NOT encrypted

packet ← "data"
OUTPUT "Eavesdropper copied the packet"

network ← "public Wi-Fi"
OUTPUT network

IF public = TRUE AND secure = FALSE THEN
   OUTPUT "Anyone can read it"
ENDIF

Section E: Spot the Error

C — Data passes through routers and other devices on its way, and any of them could copy it. The line should say router1 CAN COPY packet.

C — On public Wi-Fi other people can connect and intercept data that is not protected. The output should say the data can be copied, not that it is private.

D — The data is not encrypted, so anyone who intercepts it can read it. interceptorCanRead should be TRUE.

B — The loop should go through the devices on the path that the data travels along, not through the packet. It should be FOR EACH device IN path.

B — Anyone can join public Wi-Fi, including an eavesdropper. That is why it is a risk. The users value should say anyone can connect.