Show appreciation of the need for both the security of data and the security of the computer system

6.1 Data Security

Objective

Show appreciation of the need for both the security of data and the security of the computer system.

Why Security Matters

In modern computing, data and the systems that store, process, and transmit that data are inseparable. A breach of either can compromise the other, leading to loss of confidentiality, integrity, or availability.

Key Threats to Data

• Unauthorised access (e.g., hacking, insider threats)
• Accidental loss or deletion
• Malware that corrupts or steals data
• Interception during transmission (eavesdropping)
• Physical theft of storage media

Key Threats to the Computer System

• Unauthorised physical access to hardware
• Exploitation of software vulnerabilities
• Denial‑of‑service attacks
• Rootkits and backdoors
• Inadequate patch management

Security Measures for Data

1. Encryption – transforms plaintext into ciphertext using an algorithm and a key.

   • Symmetric (e.g., AES)
   • Asymmetric (e.g., RSA)

2. Hashing – produces a fixed‑length digest; useful for integrity checks.

   • SHA‑256, SHA‑3, etc.

3. Access control – authentication and authorisation mechanisms such as passwords, biometrics, and role‑based access.
4. Backup and recovery – regular, off‑site backups with verification.
5. Secure transmission – use of TLS/SSL, VPNs, and secure protocols (e.g., SFTP).

Security Measures for the Computer System

1. Firewalls – filter incoming and outgoing network traffic based on rules.
2. Patch management – timely installation of updates to close vulnerabilities.
3. Intrusion detection/prevention systems (IDS/IPS) – monitor for suspicious activity.
4. Physical security – locked rooms, CCTV, access cards.
5. Hardening – disabling unnecessary services, using least‑privilege accounts.

Relationship Between Data and System Security

Data security relies on a secure system, and a secure system must protect the data it handles. Weakness in one area can undermine the other.

Comparative Overview

Quantifying Password Strength

The entropy \$H\$ of a password can be estimated by:

\$H = L \times \log_2 N\$

where \$L\$ is the password length and \$N\$ is the size of the character set. Higher entropy means a lower probability \$P\$ of guessing the password:

\$P = \frac{1}{2^{H}}\$

Summary

• Both data and system security are essential for protecting information assets.
• Threats can be technical, physical, or human‑based; mitigation requires layered controls.
• Effective security combines encryption, access control, backups, firewalls, patching, and physical safeguards.
• Understanding the interplay between data and system security helps design robust, resilient solutions.