This course provides an extension of the Computer Networks introductory course and provides a more in-depth overview of Network Security issues on the different layers of Computer Networks. 

Introduction: A short summary review of the layered network model 

Network Security Introduction

• Explores the goals of security: “confidentiality”, “integrity”, “authentication”, and “availability”.
• Discusses threats like “eavesdropping”, “spoofing”, and “denial of service”.
• Introduces key strategies like “cryptography” and “secure protocols”.

Message Confidentiality

• Ensures messages can only be read by intended recipients.
• Uses “encryption techniques” like “symmetric (AES)” and “asymmetric (RSA)” cryptography.
• Involves key management and secure transmission of keys.

Message Authentication

• Verifies that a message is truly from the claimed sender and hasn’t been altered.
• Uses tools like “Message Authentication Codes (MACs)” and “digital signatures”.
• Often combined with confidentiality to provide both security goals.

Wireless Security

• Wireless networks are more vulnerable due to open-air transmission.
• Protects using “WPA2/WPA3”, “encryption”, and “authentication protocols”.
• physical security and rogue access point detection.

Web Security

• Covers “HTTPS”, “TLS”, “browser security policies”, and certificate validation.
• Fights threats like “man-in-the-middle attacks”, “cookie hijacking”, and “phishing”.
• Secure design is vital for web-based apps and e-commerce.

DNS Security

• Addresses weaknesses in the “Domain Name System”, like DNS spoofing.
• Uses “DNSSEC” to ensure authenticity and integrity of DNS responses.
• Prevents redirection to malicious domains.

Firewalls

• Controls what traffic is allowed in and out of a network.
• Types include “packet-filtering”, “stateful inspection”, and “application-layer” firewalls.
• Acts as a barrier between trusted and untrusted networks.

Virtual Private Networks (VPNs)

• Creates secure tunnels over public networks.
• Encrypts data and masks user identity/IP address.
• Often used by remote workers or to bypass geo-restrictions.

Distributed Denial of Service (DDoS)

• Attack where multiple systems flood a target, overwhelming it with traffic.
• Mitigation includes “traffic filtering”, “rate limiting”, and “content delivery networks (CDNs)”.
• Aims to ensure “availability” under attack conditions.

Upon completion of this course, learners will be able to understand and explain in details of the many security issues and topics in Computer Networks.

• Presentations
• Interactive discussions
• Questions & Answers
• Quizzes and learning checks