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9618Paper 1 · Theory Fundamentals§6.1, §6.2

6. Security, Privacy and Data Integrity

Data security vs data integrity, threats, prevention, validation and verification.

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Statometer64CoreNext Paper 176%
Marks a paper10.2 · 14%Rank#9 of 12 · #7 on P1Trend · last 12↗Oct/Nov 24 · 11: 0 · Oct/Nov 24 · 12: 10 · Oct/Nov 24 · 13: 0 · May/Jun 25 · 11: 11 · May/Jun 25 · 12: 0 · May/Jun 25 · 13: 15 · Oct/Nov 25 · 11: 9 · Oct/Nov 25 · 12: 21 · Oct/Nov 25 · 13: 14 · May/Jun 26 · 11: 18 · May/Jun 26 · 12: 13 · May/Jun 26 · 13: 5 marks8 in 10 chance in the next paper

Everything for this topic — study hub

AS Level · 9618 · Paper 1

This topic is rows 18–19 of the study route.Open it on your study route

Statometer — what 33 real papers say about this topic and each of its 2 syllabus bullets

Core · #9 of 12 in AS Level · recomputed with every new session

64CORE
Core#9 of 12 in AS Level#7 on Paper 1↗ Rising

A regular, well-paid topic — you cannot afford a gap here.

Next Paper 1
76%
8 in 10 chance it is set
Marks a paper
10.2 / 75
14% of Paper 1 · fair share 13%
Appeared in
26 / 33
Paper 1 sittings 2021–2026
Last set
May/Jun 2026
9618/13 · Q1 · 5 marks · 11-series streak
Marks in each of the last 12 Paper 1 sittingsOct/Nov 24 → May/Jun 26
Oct/Nov 24 · 11: 0 marksOct/Nov 24 · 12: 10 marksOct/Nov 24 · 13: 0 marksMay/Jun 25 · 11: 11 marksMay/Jun 25 · 12: 0 marksMay/Jun 25 · 13: 15 marksOct/Nov 25 · 11: 9 marksOct/Nov 25 · 12: 21 marksOct/Nov 25 · 13: 14 marksMay/Jun 26 · 11: 18 marksMay/Jun 26 · 12: 13 marksMay/Jun 26 · 13: 5 marks

What the papers say

  • Set in 26 of 33 Paper 1 sittings — about 8 papers in 10.
  • Worth about 10.2 marks a paper (14% of Paper 1).
  • Last set May/Jun 2026 · 9618/13 · Q1 for 5 marks — in the most recent series.
  • Set in each of the last 11 series without a miss.
  • Rising: about 8.3 marks a paper in the earlier years, 11.3 in the latest.
  • Lives on “Describe” and “Explain” — 73% of its questions: full sentences with a reason, not one-word answers.
  • 43% of its questions involve a diagram, table or figure — practise with pen and paper.
  • Its biggest question so far: 22 marks (May/Jun 2024 · 9618/13 · Q7).
  • Inside the topic, §6.1 Data security carries the most marks (51%) and §6.2 Data integrity the least (49%).
  • It is examined almost entirely as AO1 (Knowledge & understanding, 90%) — definitions and descriptions in syllabus words score.
  • The examiner has commented on 46 of its questions — read “What the examiner said” before you practise.

Command words

Share of questions using the word (a question can use several). What each wants →

Question shapes

  • ≤ 6 mk18
  • 7–9 mk13
  • 10–12 mk13
  • 13–15 mk8
  • 16+ mk8

Average 9.9 marks a question · 43% with a figure or table · 35% with code · biggest 22 marks

Assessment objectives — how it is examined

Every part of every current-syllabus question filed under Cambridge's AO1 / AO2 / AO3 (from its command word and what it asks you to do), so you know whether this topic pays for definitions, for applying, or for judging and building.

  • AO1 Knowledge & understanding
  • AO2 Apply & analyse
  • AO3 Design, program & evaluate

Paper 1 as a whole

Paper 1SyllabusMeasured
AO1 Knowledge & understanding60%68%
AO2 Apply & analyse40%32%
AO3 Design, program & evaluate0%0%

Syllabus = Cambridge's grid; measured = the bank's current-syllabus papers.

Inside the topic — every syllabus bullet, measured

Each part of each question is filed under the bullet it examines; the numbers are per Paper 1 sitting, exactly like the topic's. Open a bullet for its own Statometer.

  • 6.1Data security#13 of 25 on Paper 1Core · 5862% next paper3.3 marks21/33 sittings↘ May/Jun 2026

    A regular earner inside the topic — most papers touch it.Syllabus: security, privacy, integrity; threats; protecting systems (accounts, passwords, digital signatures, biometrics, firewalls, anti-malware) and data (encryption, access rights)

    Next Paper 1
    62%
    6 in 10
    Marks a paper
    3.3
    4% of the paper · 51% of the topic
    Asked in
    21 / 33
    Paper 1 sittings · 39 questions
    Last asked
    May/Jun 2026
    9618/12 · Q2 · 6 marks · 11-series streak
    • Asked in 21 of 33 Paper 1 sittings — about 6 papers in 10.
    • About 3.3 marks a paper (4% of Paper 1; 51% of the topic's marks across its 2 bullets).
    • Last asked May/Jun 2026 · 9618/12 · Q2 (6 marks) — in the most recent series.
    • Asked in each of the last 11 series.
    • Easing: 4 → 2.9 marks a paper.
    • Usually “Describe” or “Explain”: full sentences with a reason, not one-word answers.
    • Biggest chunk of marks so far: 10 in May/Jun 2022 · 9618/12 · Q4.
    • It is examined almost entirely as AO1 (Knowledge & understanding, 97%) — definitions and descriptions in syllabus words score.
    Last 12 sittings↘ Easing
    Oct/Nov 24 · 11: 0 marksOct/Nov 24 · 12: 3 marksOct/Nov 24 · 13: 0 marksMay/Jun 25 · 11: 8 marksMay/Jun 25 · 12: 0 marksMay/Jun 25 · 13: 4 marksOct/Nov 25 · 11: 5 marksOct/Nov 25 · 12: 3 marksOct/Nov 25 · 13: 2 marksMay/Jun 26 · 11: 0 marksMay/Jun 26 · 12: 6 marksMay/Jun 26 · 13: 0 marks

    Assessment objectives

    • AO1 Knowledge & understanding
    • AO2 Apply & analyse
    • AO3 Design, program & evaluate
    • Describe69%
    • Explain56%
    • Complete36%
    • Give33%
    Practise its 39 questionsBiggest: 10 marks · May/Jun 2022
  • 6.2Data integrity#14 of 25 on Paper 1Core · 5659% next paper3.1 marks19/33 sittings↗ May/Jun 2026

    A regular earner inside the topic — most papers touch it.Syllabus: validation (range, format, length, presence, existence, limit, check digit); verification on entry (visual, double entry) and on transfer (parity byte/block, checksum)

    Next Paper 1
    59%
    6 in 10
    Marks a paper
    3.1
    4% of the paper · 49% of the topic
    Asked in
    19 / 33
    Paper 1 sittings · 42 questions
    Last asked
    May/Jun 2026
    9618/13 · Q1 · 5 marks · 3-series streak
    • Asked in 19 of 33 Paper 1 sittings — about 6 papers in 10.
    • About 3.1 marks a paper (4% of Paper 1; 49% of the topic's marks across its 2 bullets).
    • Last asked May/Jun 2026 · 9618/13 · Q1 (5 marks) — in the most recent series.
    • Rising: 2.6 → 3.7 marks a paper.
    • Usually “Describe” or “Explain”: full sentences with a reason, not one-word answers.
    • Biggest chunk of marks so far: 7 in May/Jun 2026 · 9618/12 · Q2.
    • It is examined almost entirely as AO1 (Knowledge & understanding, 96%) — definitions and descriptions in syllabus words score.
    Last 12 sittings↗ Rising
    Oct/Nov 24 · 11: 0 marksOct/Nov 24 · 12: 0 marksOct/Nov 24 · 13: 0 marksMay/Jun 25 · 11: 3 marksMay/Jun 25 · 12: 0 marksMay/Jun 25 · 13: 0 marksOct/Nov 25 · 11: 0 marksOct/Nov 25 · 12: 10 marksOct/Nov 25 · 13: 6 marksMay/Jun 26 · 11: 5 marksMay/Jun 26 · 12: 7 marksMay/Jun 26 · 13: 5 marks

    Assessment objectives

    • AO1 Knowledge & understanding
    • AO2 Apply & analyse
    • AO3 Design, program & evaluate
    • Describe60%
    • Explain52%
    • State38%
    • Complete33%
    Practise its 42 questionsBiggest: 7 marks · May/Jun 2026

34% of the topic's marks sit in question parts that belong to another topic (scenario questions cross sections) or that no bullet claims; they count for the topic, not for a bullet.

Marks a paper, year by year

151617181920212223242526

Grey years are the previous syllabus (2015–2021, 30 questions) — history, not counted in the rates.

By exam series

  • May/Jun15/18 · 10.2 mk
  • Oct/Nov11/15 · 9 mk
Practise 60 real questions Smart Notes Quiz Flashcards Every topic on the Statometer

What you need to know2syllabus §6.1, §6.2

  1. 6.1Data security — security, privacy, integrity; threats; protecting systems (accounts, passwords, digital signatures, biometrics, firewalls, anti-malware) and data (encryption, access rights)
  2. 6.2Data integrity — validation (range, format, length, presence, existence, limit, check digit); verification on entry (visual, double entry) and on transfer (parity byte/block, checksum)

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Infographics3draw these the way the examiner expects · download as PNG

Error detection methodsData can be corrupted by interference during transmission. Each method answers: how is the error found?Parity checkEven parity: number of 1s must be even.1011 0010 → four 1s ✓ (parity bit = bit 8)Fails if two bits flip. A parity block(rows + columns) can locate the bad bit.ChecksumSender adds all bytes, sends the total.Receiver recalculates and compares.Mismatch → request the block again.Cheap; catches most bursts of errors.Echo checkReceiver sends the data straight back.Sender compares it with the original.Weakness: which copy got corrupted?Used with retransmission.Check digitAn extra digit calculated from the other digits (ISBN-13,barcodes: modulo-10 weighting). Recalculated on entry —catches a wrong, missing or transposed digit.ARQ — Automatic Repeat reQuestReceiver checks the data (parity / checksum). Correct →sends ACK. Error, or no ACK before the time-out →the sender automatically retransmits the block.Symmetric encryption: one shared key encrypts and decrypts. Asymmetric: public key encrypts, matching private key decrypts.Encryption protects meaning if data is intercepted — it does not detect errors. Parity, checksum and echo check do.cswithzak.com

Error detection methods

O LevelAS
Cyber security: threats vs defencesAim → describe the threat, its effect on the data or user, and the matching prevention. Always pair themup.ThreatWhat happensPrevent it withBrute-forcetrying every possible password until one workslong complex passwords, lock-out, 2FADDoSa botnet floods a server with requests until it failsfirewall, proxy server, traffic filteringHackingunauthorised access to a system to steal or change datafirewall, strong passwords, 2FA, encryptionMalwarevirus, worm, Trojan, spyware, adware, ransomwareanti-malware, updates, backupsPhishingfake email/text lures you to a fake site to enter detailscheck sender & URL, spam filter, awarenessPharmingmalicious code redirects a real URL to a fake websitecheck SSL certificate/padlock, anti-malwareSocial engineeringmanipulating people rather than systems (calls, pretexts)staff training, verify requests, policiesDefence toolkitaccess levelsanti-malwareauthenticationbiometricstwo-factor (2FA)firewallprivacy settingsproxy serverSSL / HTTPSauto-updatesbackupsEncryption makes intercepted data unreadable without the key. Firewall: filters traffic by rules. Proxy: also hides the real server.Virus: needs a host file · Worm: self-replicates across the network · Trojan: hides in legitimate-looking softwareSpyware: records keystrokes · Adware: unwanted adverts · Ransomware: encrypts your files until you paycswithzak.com

Cyber threats vs defences

O LevelAS
Data security · privacy · integrityThree ideas examiners love to see confused: security keeps data safe, privacy keeps it confidential,integrity keeps it correct.SECURITYprotecting data from loss, corruption andunauthorised access• backups & disaster recovery• user accounts, passwords, 2FA• access rights / permissions• firewall, anti-virus, updates• encryption of stored + sent dataPRIVACYkeeping personal data confidential — onlyseen by those entitled• data protection law & policies• privacy settings, consent• anonymising data sets• encryption so intercepted data• cannot be readINTEGRITYdata is accurate, consistent and up todate• validation on input• verification of transfer / entry• referential integrity in a DB• parity / checksum on transmission• no duplicates or contradictionsThreats to computer & datamalware (virus, worm, spyware, ransomware) · hackers · phishing (fake email/site) · pharming (redirect via DNS/host file) · accidental losshardware failure · disaster · disgruntled staff. Match each to a control: backup, access rights, encryption, firewall, anti-malware.Validation checksrange · type · length · format · presenceuniqueness · check digit · limit · consistency(checks data is sensible, NOT that it is true)Verificationon entry: double entry, visual checkduring transfer: parity, checksum, echo check(checks the data was copied/typed correctly)Classic 4-marker: “difference between data security and data integrity” — safe from harm vs correct and consistent.cswithzak.com

Security, privacy & integrity

AS

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Key terms9use these exact words in the exam

data integritydata securitymalwarephishingpharmingvalidationverificationchecksumparity

Dotted terms are defined in the glossary.

Code help2referenced to the Cambridge pseudocode guide

Check-digit validation (modulus 11, ISBN-10 style)

pseudocode §5.5, §7.1 Run in Playground
DECLARE Code : STRING
DECLARE i, Sum, Check : INTEGER
Code ← "020161622"      // first 9 digits
Sum ← 0
FOR i ← 1 TO 9
   Sum ← Sum + STR_TO_NUM(MID(Code, i, 1)) * (11 - i)
NEXT i
Check ← (11 - (Sum MOD 11)) MOD 11
OUTPUT "Check digit: ", Check

Format check: ID must be 2 letters + 4 digits

pseudocode Run in Playground
FUNCTION IsLetter(C : CHAR) RETURNS BOOLEAN
   RETURN UCASE(C) >= 'A' AND UCASE(C) <= 'Z'
ENDFUNCTION
FUNCTION IsDigit(C : CHAR) RETURNS BOOLEAN
   RETURN C >= '0' AND C <= '9'
ENDFUNCTION
DECLARE ID : STRING
DECLARE OK : BOOLEAN
DECLARE i : INTEGER
ID ← "AB1234"
OK ← LENGTH(ID) = 6 AND IsLetter(MID(ID,1,1)) AND IsLetter(MID(ID,2,1))
FOR i ← 3 TO 6
   OK ← OK AND IsDigit(MID(ID, i, 1))
NEXT i
OUTPUT ID, " valid: ", OK

Playground examples7runnable programs for this topic

  • Caesar cipher — encrypt & decrypt

    Shift letters with ASC and CHR, wrapping with MOD 26. Same key both ways = symmetric encryption.

    O LevelASA2PseudocodeString handling §5.5 · 2210 §5 / 9618 §6.2 security
    Run

  • Range check

    Keep asking until the value is between 0 and 100.

    O LevelASPseudocodeValidation, testing & exceptions 2210 §7.3 / 9618 §6.2
    Run

  • Presence & length checks

    Nothing entered? Too short or too long? Say which check failed.

    O LevelASPseudocodeValidation, testing & exceptions 2210 §7.3 / 9618 §6.2
    Run

  • Type check — digits only

    A function that tests every character before the string is converted to a number.

    O LevelASPseudocodeValidation, testing & exceptions 2210 §7.3 / 9618 §6.2
    Run

  • Format check — is this an email address?

    One @ that is not first, and a dot after it that is not last.

    O LevelASPseudocodeValidation, testing & exceptions 2210 §7.3 / 9618 §6.2
    Run

  • Check digit — ISBN-13

    Weights 1 and 3 alternate, total MOD 10, subtract from 10. The classic check-digit algorithm.

    O LevelASPseudocodeValidation, testing & exceptions 2210 §2.3, §7.3
    Run

  • Verification — double entry

    Validation checks the data is sensible; verification checks it was entered correctly.

    O LevelASPseudocodeValidation, testing & exceptions 2210 §7.3 / 9618 §6.2
    Run

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Quiz: Security, Privacy & Data Integrity (46)🃏 Flashcards: mix this topic (41)⚖️ Data security & privacy (23)✅ Data integrity — validation & verification (18)Past-paper questions (60)🧪 Validation & check digits🔐 Encryption lab🪤 Examiner's traps🎮 Play ArenaZ🎮 Play RoyaleZ🎮 Play PacketZ🎮 Play SpireZ🎮 Play ImposterZ

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