# Unit information: Cryptography A in 2018/19

Please note: It is possible that the information shown for future academic years may change due to developments in the relevant academic field. Optional unit availability varies depending on both staffing and student choice.

Unit name Cryptography A COMS30002 10 H/6 Teaching Block 1 (weeks 1 - 12) Dr. Stam Not open COMS20002 or a comparable background in discrete mathematics None Department of Computer Science Faculty of Engineering

## Description

Cryptography is a highly interdisciplinary field, with a lengthy and interesting history stemming from mathematical roots. Starting from historical ciphers (e.g., letter substitution etc.), the aim of this unit is to introduce various fundamentals of cryptography from a modern perspective. The main focus is design and security aspects of schemes used to ensure secrecy and authenticity; we all routinely rely on such schemes in use-cases such as network communication and storage.

The syllabus will include aspects of (but is not limited to):

• Mathematical preliminaries: basic modular arithmetic (inc. CRT); basic group and field theory; fundamental algorithms (e.g., GCD); cryptographic reductions.
• Symmetric cryptography: security models and proofs; encryption schemes (e.g., AES); cryptographic hash functions and MACs; modes of operation (e.g., CBC, CTR etc.); basic cryptanalysis.
• Asymmetric cryptography: security models and proofs; encryption schemes (e.g., RSA and ElGamal); digital signature schemes (e.g., RSA signatures, or DSA); modes of operation (i.e., padding schemes etc.); basic cryptanalysis.

## Intended learning outcomes

After following this unit you should be able to:

• Explain and apply the principles of modern cryptology in the context of secure communication
• Explain and demonstrate the functionality and desired security of standard cryptographic schemes used for confidentiality and authenticity.
• Link the design and operation of standard, state-of-the-art symmetric and asymmetric cryptographic schemes to their mathematical underpinnings.
• Use basic cryptanalytic techniques to evaluate the security level of simple cryptographic schemes.

## Teaching details

20 hours of lectures (2 hours per week), 10 hours of (supervised, but non-taught) problem classes (1 hour per week).

100% exam