## COMP3223 Cryptography

### 10 creditsClass Size: 200

Module manager: Dr Toni Lassila
Email: T.Lassila@leeds.ac.uk

Taught: Semester 2 (Jan to Jun) View Timetable

Year running 2020/21

### Pre-requisites

 COMP1511 Introduction to Discrete Mathematics

This module is not approved as a discovery module

### Module summary

This module provides a thorough introduction to cryptography and its applications. We cover the mathematical foundations of cryptography and discuss modern cryptosystems in detail. This includes both symmetric and public-key systems like AES and RSA and their usage and applications in digital signatures and complex cryptographic protocols like digital money and electronic voting.

### Objectives

On completion of this module, students should be able to:
-Know and apply fundamental cryptographic techniques and algorithms.
-Understand and apply the principles of modern symmetric and public-key cryptosystems and further cryptographic primitives such as hash functions.
-Apply appropriate known cryptographic techniques for a given scenario.
-Understand the dangers of inventing one’s own cryptographic methods.
-Explain how key exchange protocols work and how they fail.
-Explain how Public Key Infrastructure supports digital signing and encryption and discuss the limitations/vulnerabilities.
-Discuss the importance of modular arithmetic and prime numbers in cryptography and explain their use in cryptographic algorithms.
-Explain the role of random numbers in security, beyond just cryptography (eg password generation, randomized algorithms)
-Describe quantum cryptography and the impact of quantum computing on cryptographic algorithms.
-Describe likely attacker types against a particular system.
-Describe risks to privacy and anonymity in commonly used applications.
-Describe real-world applications of cryptographic primitives and protocols.
-Discuss cryptographic protocols and their properties.

Learning outcomes
On completion of the year/programme students should have provided evidence of being able to:
-understand and demonstrate coherent and detailed subject knowledge and professional competencies some of which will be informed by recent research/scholarship in the discipline;
-deploy accurately standard techniques of analysis and enquiry within the discipline;
-demonstrate a conceptual understanding which enables the development and sustaining of an argument;
-describe and comment on particular aspects of recent research and/or scholarship;
-appreciate the uncertainty, ambiguity and limitations of knowledge in the discipline;
-make appropriate use of scholarly reviews and primary sources;
-apply their knowledge and understanding in order to initiate and carry out an extended piece of work or project;

### Syllabus

Cryptographic goals. Cryptanalysis of classical ciphers, Modern symmetric crpytosystems: DES, AES and its operation modes.
Mathematical foundations of public-key cryptography: modular arithmetic, Extended Euclidian Algorithm, efficient exponentiation, prime number generation, Chinese Remainder Theorem, Miller-Rabin test.
Public-key cryptography: RSA, ElGamal, Diffie-Hellman key exchange. Digital signatures, Hash functions, Quantum cryptography and the impact of quantum computing.
Different types of attacks, Classification of cryptosystems in terms of security, Cryptographic design principles, Applications and cryptographic protocols: digital money, secure elections

### Teaching methods

Due to COVID-19, teaching and assessment activities are being kept under review - see module enrolment pages for information

 Delivery type Number Length hours Student hours Class tests, exams and assessment 1 2.00 2.00 Lecture 22 1.00 22.00 Private study hours 76.00 Total Contact hours 24.00 Total hours (100hr per 10 credits) 100.00

### Private study

Taught session preparation: 18 hours
Taught session follow-up: 18 hours
Self-directed study: 10 hours
Assessment activities: 30 hours

### Opportunities for Formative Feedback

Attendance and formative assessment

### Methods of assessment

Due to COVID-19, teaching and assessment activities are being kept under review - see module enrolment pages for information

Coursework
 Assessment type Notes % of formal assessment In-course Assessment Exercises based on lectures 1-10 20.00 In-course Assessment Exercises based on lectures 11-20 20.00 Total percentage (Assessment Coursework) 40.00

This module will be reassessed by an online time-constrained assessment.

Exams
 Exam type Exam duration % of formal assessment Online Time-Limited assessment 48 hr 00 mins 60.00 Total percentage (Assessment Exams) 60.00

This module will be reassessed by an online time-constrained assessment.