Data Security, Cryptography and Attack

What Data Security, Cryptography and Attack covers

Data Security, Cryptography and Attack is examined in A2 Unit 4, Computer Architecture, Data, Communication and Applications. It covers integrity problems in online updating, the need for cryptography, symmetric and asymmetric techniques, Classical ciphers and cryptographic algorithms, comparing cryptographic strength, biometric technologies, malicious software and its vectors and attacks, defence and penetration testing.

The 8 subtopics

Each one has its own page.

• Integrity problems in online updatingOnline updating, concurrent update problem and record locking.Open →
• The need for cryptographyKey, in cryptography and four objectives cryptography is used to achieve.Open →
• Symmetric and asymmetric techniquesSymmetric encryption, key distribution problem and hybrid arrangement.Open →
• Classical ciphers and cryptographic algorithmsSubstitution cipher, transposition cipher and caesar cipher.Open →
• Comparing cryptographic strengthBrute force attack and balanced conclusion about cryptographic strength.Open →
• Biometric technologiesBiometric authentication, four biometric characteristics in contemporary use and false acceptance.Open →
• Malicious software and its vectorsInformation does spyware typically gather, attack vector and zero-day vulnerability.Open →
• Attacks, defence and penetration testingSpear phishing, SQL injection and brute force login attack.Open →

What you need to know

Answer each one before you reveal it.

Take Data Security, Cryptography and Attack further

The same content, four other ways.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What is online updating?

   Model answer

   Amending a file or database directly as each transaction occurs, rather than collecting transactions and applying them in a batch.

2. 2

   Why does online updating create integrity problems a batch update does not?

   Model answer

   Several users can change the same data at the same instant, and there is no single controlled run in which the order of changes is known.

3. 3

   What is the concurrent update problem?

   Model answer

   Two users read the same record, each amends their copy, and the second write overwrites the first, so one update is lost.

4. 4

   Give a concrete example of a lost update.

   Model answer

   Two agents each read a stock level of one seat, each sells it, and each writes zero — so two seats are sold and only one existed.

5. 5

   What is record locking?

   Model answer

   Preventing other users from writing to a record while one user is amending it.

6. 6

   Distinguish an exclusive lock from a shared lock.

   Model answer

   An exclusive lock prevents any other access while a record is being written; a shared lock allows others to read but not to write.

What is inside Levo

Six ways to work the same material.

Data Security, Cryptography and Attack revision questions

What does Data Security, Cryptography and Attack cover in WJEC A-Level Computer Science?

8 subtopics: integrity problems in online updating, the need for cryptography, symmetric and asymmetric techniques, classical ciphers and cryptographic algorithms, comparing cryptographic strength, biometric technologies, malicious software and its vectors and attacks, defence and penetration testing. Each one has its own page with questions and model answers.

How is Data Security, Cryptography and Attack organised?

By the WJEC 601-5345-3 specification, subtopic by subtopic, so it matches the order you are taught it in.