Introductory description

Cryptography is an essential tool in modern cyber security. It allows us to protect sensitive information, authenticate users and devices, and enable secure communication over insecure networks. Cryptographic techniques are used in a wide range of contexts, including secure messaging, protecting online transactions, and virtual private networks (VPNs). This module provides an introduction to the fundamental concepts of symmetric-key and public-key cryptography, and their practical applications.

Module aims

Outline syllabus

This is an indicative module outline only to give an indication of the sort of topics that may be covered. Actual sessions held may differ.

Introduction to cryptography:

• Why do we need cryptography?
• Historical encryption schemes

Symmetric-key encryption:

• Block ciphers: DES, 3DES, AES
• Stream ciphers and block cipher modes of operation
• Constructions: Feistel structures and substitution-permutation (SP) networks
• Entropy and key length
• The key exchange problem

Public-key encryption:

• RSA and elliptic-curve cryptography
• Hybrid-key encryption
• Public-key infrastructure (PKI) and key authentication

Hash algorithms:

• Properties: Irreversible, deterministic, collision resistance, length
• Algorithms: MD5, SHA
• Applications: Authentication, known good/bad files, file integrity
• Known weaknesses: Attacks including brute force, rainbow tables and length extension attacks

Message authentication:

• Message authentication codes (MACs)
• Digital signatures

Important protocols:

• TLS and X509 certificates
• PGP

The future of cryptography:

• Overview of blockchains and cryptocurrencies
• Introduction to post-quantum cryptography

Learning outcomes

By the end of the module, students should be able to:

• Be familiar with commonly used cryptographic primitives and protocols
• Critically evaluate the properties of different cryptographic algorithms
• Be able to design secure cryptosystems that meet different application requirements
• Evaluate the use of different cryptographic techniques used to build cryptosystems

Indicative reading list

Wong, D., 2021. Real-World Cryptography. Manning Publications.
Schneier, B., Kohno, T. and Ferguson, N., 2013. Cryptography engineering: design principles and practical applications. Wiley.
Anderson, R., 2021. Security Engineering. John Wiley & Sons.

View reading list on Talis Aspire

Interdisciplinary

Cryptography is an inherently interdisciplinary subject. It combines ideas from mathematics, electronics and computer science together with social studies on the usability of secure systems, and these will be demonstrated throughout the module.

Subject specific skills

This course enables students to develop an understanding of the fundamentals of cryptography, knowledge of cryptographic algorithms and when to use them, as well as an ability to use cryptography to build secure systems.

Transferable skills

Critical thinking, problem solving, written communication skills, and the ability to independently build large, secure systems