# Security, privacy and data integrity

> CIE A-Level Computer Science · 9618 Paper 1 & 2
> Source: https://www.owlsprep.com/study/cie-9618-u6-overview/
> Weight: n/a

This unit explores core concepts for protecting computer systems and user data, covering common threats, technical protection mechanisms, integrity safeguards, privacy regulations, and disaster recovery strategies, a core topic for both CIE 9618 papers.

**Prerequisites:** Basic understanding of computer networks and binary data representation

## Learning objectives

- Identify and classify common security threats to computer systems and user data
- Explain how encryption, access control, and integrity checks protect information assets
- Evaluate organizational strategies for backup, disaster recovery, and compliance with privacy regulations
- Discuss ethical trade-offs between data collection, security, and individual privacy

## Unit at a glance

This unit follows a logical learning arc: you will first learn what can go wrong with system security, then explore technical safeguards to mitigate those risks, before covering organizational policies and ethical considerations related to data protection.

Each sub-topic builds on the previous to give you a complete end-to-end framework for information protection, from threat identification to post-failure recovery.

This unit includes the following sub-topics:
- [Threats to security](https://www.owlsprep.com/study/cie-9618-u6-threats-to-security/) — Classifies common internal and external security threats to computer systems and data.
- [Encryption](https://www.owlsprep.com/study/cie-9618-u6-encryption/) — Covers symmetric, asymmetric encryption, hashing, and their common use cases for data protection.
- [Access control](https://www.owlsprep.com/study/cie-9618-u6-access-control/) — Explores methods to restrict system access to only authorized authenticated users.
- [Data integrity](https://www.owlsprep.com/study/cie-9618-u6-data-integrity/) — Covers parity checks, checksums, and other methods to detect and prevent data corruption.
- [Privacy issues](https://www.owlsprep.com/study/cie-9618-u6-privacy-issues/) — Discusses ethical, legal, and regulatory requirements for protecting personal user data.
- [Backup and recovery](https://www.owlsprep.com/study/cie-9618-u6-backup-and-recovery/) — Explains backup strategies and disaster recovery plans for data after system failure or breach.

## Common pitfalls

- **Wrong:** Confusing encryption with hashing
  - Why it fails: Many students mix up these two concepts, forgetting their core purposes differ significantly
  - Correct: Encryption is reversible with a key (used to hide data), while hashing is one-way (used to verify data integrity)
- **Wrong:** Mixing up data security and data integrity
  - Why it fails: These are overlapping but distinct concepts that are often tested separately
  - Correct: Security prevents unauthorized access to data, while integrity prevents unauthorized modification or corruption of data

## Cheatsheet

| Concept | Key Summary |
| --- | --- |
| Threat classification | Categorized as accidental/deliberate, internal/external, malware/social engineering |
| Symmetric encryption | Uses one shared secret key for encryption/decryption; fast for large datasets |
| Asymmetric encryption | Uses public/private key pair; used for key exchange and digital signatures |
| Hashing | One-way function producing a fixed-length digest; used for integrity and password storage |
| Data integrity checks | Common methods: parity bits, checksums, CRC, cryptographic hashing |
| 3-2-1 Backup Rule | 3 copies of data, 2 stored on different media types, 1 copy stored offsite |

## What's next

Ready to start this unit? Begin with the first sub-topic on threats to security, where you will learn to identify and classify different types of risks that can compromise computer systems and data. Once you complete all sub-topics in this unit, you can move on to the next unit on artificial intelligence to continue your CIE A-Level 9618 preparation.

- [Threats to security](https://www.owlsprep.com/study/cie-9618-u6-threats-to-security/)
- [Encryption](https://www.owlsprep.com/study/cie-9618-u6-encryption/)
- [Access Control](https://www.owlsprep.com/study/cie-9618-u6-access-control/)

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