AS & A Level Computer Science 9618 · Topic 17

Security: past paper questions

9 real questionsasked in 4 of the last 9 exam series2022–2025usually: Explain, Describe, Identify, Outline, State

Real questions on security

The newest 9 of 9 written questions. Open one to see it on the real paper.

9618/31 · October/November 2025 · Q5a[2]
Identify two items commonly found within a digital certificate.
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9618/31 · October/November 2025 · Q5b[3]
Explain why a digital certificate is required to validate a digital signature.
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9618/33 · October/November 2025 · Q9[4]
A company requires a digital certificate to ensure the authenticity of its online communications. Outline the process followed to acquire a digital certificate.
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9618/33 · May/June 2024 · Q7a[3]
Describe what is meant by a digital certificate.
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9618/32 · May/June 2023 · Q5a[2]
Encryption is used to scramble data to make it meaningless if intercepted. Describe the purpose of quantum cryptography.
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9618/32 · May/June 2023 · Q5b[3]
Explain the differences between symmetric and asymmetric cryptography when encrypting and decrypting data.
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9618/12 · October/November 2022 · Q6a(i)[2]
Explain how a digital signature ensures the email is authentic.
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9618/32 · October/November 2022 · Q6a[2]
State two differences between symmetric and asymmetric encryption.
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9618/32 · October/November 2022 · Q6b[4]
Explain the process by which an organisation may acquire its digital certificate.
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What examiners said

Candidates who described the purpose of quantum cryptography, such as ‘to produce a virtually unbreakable encryption system’, rather than simply describing quantum cryptography or how it works, achieved the marks.
— Examiner report, May/June 2023, 9618/32 Q5(a) (Cambridge)

Candidates who gave differences between symmetric and asymmetric encryption by including both encryption types in their response achieved marks. However, many responses described only one difference in detail, rather than giving a comprehensive answer with several differences.
— Examiner report, May/June 2023, 9618/32 Q5(b) (Cambridge)

Many candidates found this question challenging. Responses included vague references to encrypting and decrypting keys, without identifying them as private and public and with little reference to which key would be used for encryption and which for decryption. There was a lot of confusion with using a finger or stylus to sign on a touchscreen device.
— Examiner report, October/November 2022, 9618/12 Q6(a)(i) (Cambridge)

Practise this topic

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Practise security

In the syllabus

17.1 Encryption, Encryption Protocols and Digital certificates

Including the use of public key, private key, plain text, cipher text, encryption, symmetric key cryptography and asymmetric key cryptography How the keys can be used to send a private message from the public to an individual/ organisation How the keys can be used to send a verified message to the public How data is encrypted and decrypted, using symmetric and asymmetric cryptography Purpose, benefits and drawbacks of quantum cryptography
Purpose of SSL / TLS
Use of SSL/TLS in client-server communication Situations where the use of SSL/TLS would be appropriate
How a digital certificate is acquired How a digital certificate is used to produce digital signatures

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