# Unit information: Cryptography A in 2016/17

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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