S4 ICT: Network Security And Data Protection (Paper 4 (error Clinic))

S4 ICT: Network Security and Data Protection (Paper 4 (error clinic))

2026-11-14

Tutor Prep Guide · network security and data protection: password entropy and key spaces, phishing and social engineering, malware, firewall rules, symmetric and asymmetric encryption, hashing, two-factor authentication, 3-2-1 backup and quantified risk

S4 ICT: Network Security and Data Protection (Paper 4 (error clinic))

Paper 4 (error clinic): ten questions on network security and data protection, with answers and notes.

Direct answers　Level: S4 ICT; format: password space and entropy, phishing and social engineering, malware, firewall rules, encryption and hashing, 2FA, 3-2-1 backup.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	20
Difficulty mix	Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1
Chapter	Chapter: S4 ICT: Network Security and Data Protection
Level	S4

02　Questions (10 items)

FoundationLengthening an eight-character lower-case password to twelve characters multiplies its combinations by how much?
FoundationHow many combinations does a six-character lower-case password have?
FoundationAn old identifier has only 32 bits and a billion values can be tried per second. How many seconds to exhaust it?
IntermediateWhat is the most typical feature of a phishing email?
IntermediateWhat is the main difference between a virus and a worm?
IntermediateWhat characterises a Trojan horse?
ChallengeA computer is hit by ransomware. What is the first step?
ChallengeA wireless network still uses WEP encryption. What should be done?
ChallengeWhat is the most effective defence against credential stuffing?
Error redoA student says updates are a hassle and can wait until there is time. What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	456,976 times	26 to the power of (12 minus 8) is 26 to the fourth, 456,976, so length beats fancy characters.
2	308,915,776	26 to the power of 6 is 308,915,776, which a serious tool exhausts in minutes, so the length is clearly too short.
3	About 4.29 seconds	2 to the 32 is 4,294,967,296, divided by 10 to the 9 gives about 4.29 seconds, so such a length offers no protection.
4	It impersonates a known organisation and pushes a link to a fake login page to harvest credentials	Common signs are a look-alike misspelt domain, urgent tone and a link asking for a password; genuine organisations never ask for a password by email.
5	A virus needs a host file and a user to open it, while a worm copies itself across the network unaided	A worm spreads machine to machine without any user action, which is why patching matters more than telling people not to open attachments.
6	It disguises itself as normal or useful software so the user installs it and it opens a back door	A Trojan does not self-propagate; it waits to be installed, and free utilities from unknown sources are the usual wrapper.
7	Disconnect it from the network at once, keep the machine for evidence and restore from the offline backup	Cutting the network stops the encryption spreading to network drives; paying does not guarantee a key and funds the attackers.
8	WEP is broken, so move to WPA2 or WPA3	A WEP key falls in minutes and anyone nearby can read the traffic, so only WPA2 or WPA3 counts as encryption.
9	A unique password per site plus two-factor authentication and lockout on repeated failures	Stuffing replays leaked pairs from one breach on other sites; unique passwords make a leak useless and 2FA stops a stolen password from logging in.
10	Wrong: exploits appear quickly once a flaw is public, and unpatched machines fall first	Updates belong in the next maintenance window with a backup taken first; delaying leaves a known door open.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

For password strength, fix the character set then multiply by length, since each extra bit doubles the work; for phishing check the domain first, and after ransomware disconnect the network before restoring from an offline backup instead of guessing.Tutor Registration →

Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.