Edexcel IGCSEComputer ScienceGeneral Applications7 Marks

A network administrator is setting up a new server. (a) Explain the purpose of a firewall in network security. (3) (b) Describe how 'encryption' helps to secure data transmitted over a network. (4)

(a)Explain the purpose of a firewall in network security.[3]
(b)Describe how 'encryption' helps to secure data transmitted over a network.[4]

Mark scheme

Marking points from the official mark scheme. The mark or mark type is shown in brackets.

15(a)
Monitors incoming and outgoing network traffic (B1)
Blocks/allows traffic based on a set of predetermined security rules (B1)
Acts as a barrier between a trusted internal network and untrusted external network (e.g., the internet) (B1)
Protects against unauthorised access / hacking / malware (B1)
Max 3 marks.
15(b)
Encryption scrambles/encodes data (B1)
Using an algorithm and a key (B1)
Making it unreadable/unintelligible to unauthorised users (B1)
If intercepted, the data appears as gibberish (B1)
Requires the correct key to decrypt/decode it back into its original form (B1)
Ensuring confidentiality / integrity of data during transmission (B1).
Max 4 marks.

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