Data Security, Cryptography and Attack

What Data Security, Cryptography and Attack covers

Data Security, Cryptography and Attack is examined in Component 2, Computer Architecture, Data, Communication and Applications. It covers online updating and the integrity of shared files, dangers of holding personal data, clerical procedures, access levels, passwords and write protection, cryptography: its purpose, and symmetric and asymmetric keys, hashing, digital signatures and certificates, Caesar and Vernam ciphers and comparing cipher strength, biometric technologies and their limitations, threats, damage and contingency planning and malicious software, hacking and penetration testing.

The 9 subtopics

Each one has its own page.

• Online updating and the integrity of shared filesOnline updating of a file, concurrent access problem and lost update problem.Open →
• Dangers of holding personal dataThree dangers that arise from holding files of personal data, identity theft and data profiling.Open →
• Clerical procedures, access levels, passwords and write protectionStandard clerical procedure in data security, levels of permitted access and access levels in a school information system.Open →
• Cryptography: its purpose, and symmetric and asymmetric keysNeed for cryptography when data travels over a public network, terms plaintext and ciphertext and encryption key.Open →
• Hashing, digital signatures and certificatesHash function, collision in hashing and why hashing is not encryption.Open →
• Caesar and Vernam ciphers and comparing cipher strengthBrute force attack on a cipher, how frequency analysis breaks a simple substitution cipher and three conditions a Vernam cipher must meet to be unbreakable.Open →
• Biometric technologies and their limitationsBiometric authentication, four biometric characteristics in common use and stages of enrolling a user in a biometric system.Open →
• Threats, damage and contingency planningFour potential threats to a computer system, difference between malicious and accidental damage and accidental damage to data.Open →
• Malicious software, hacking and penetration testingComputer virus, three vectors by which malware reaches a computer and black hat hacking.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.

Commonly confused

Pairs that lose marks when they are blurred together.

• False acceptance vs False rejection

  False acceptance: admitting the wrong person. False rejection: turning away the right one, and tightening the threshold trades one for the other.

• Virus vs Worm

  Virus: needing a host file and a user action to spread. Worm: copying itself across a network unaided.

• Backup vs Contingency plan

  Backup: the copy of the data. Contingency plan: the tested procedure for using it.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What is meant by online updating of a file?

   Model answer

   Online updating changes the master file immediately as each transaction is entered. The file stays live and available to other users at the same time.

2. 2

   Why does online updating create problems that batch updating avoids?

   Model answer

   A batch update runs alone on the file at a quiet time with nobody else using it. Online updating has many users writing to one live file at once.

3. 3

   What is meant by a concurrent access problem?

   Model answer

   A concurrent access problem arises when two users change the same record at the same moment. One user's change can overwrite the other's without any warning.

4. 4

   Describe the lost update problem.

   Model answer

   Two users read the same record and each writes back a changed version. The second write replaces the first, so one of the changes disappears.

5. 5

   What is record locking?

   Model answer

   Record locking stops any other user writing to a record while one user is editing it. The lock is released once the update is complete.

6. 6

   Give one drawback of record locking.

   Model answer

   Other users are held up until the lock is released. A user who leaves a record open on screen blocks everybody else.

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 Eduqas A-Level Computer Science?

9 subtopics: online updating and the integrity of shared files, dangers of holding personal data, clerical procedures, access levels, passwords and write protection, cryptography: its purpose, and symmetric and asymmetric keys, hashing, digital signatures and certificates, caesar and vernam ciphers and comparing cipher strength, biometric technologies and their limitations, threats, damage and contingency planning and malicious software, hacking and penetration testing. Each one has its own page with questions and model answers.

How is Data Security, Cryptography and Attack organised?

By the Eduqas A500QS specification, subtopic by subtopic, so it matches the order you are taught it in.