Course Structure

What to expect from this course?

The following gives a brief overview of the contents of each chapter in this course:

• Basic Principles

  This chapter explains why cryptography is needed and identifies some of the core security services that cryptography can provide.

• Historical Cryptosystems

  This chapter provides an overview of historical encryption algorithms. Most of these are obsolete today, but they illustrate many of the core ideas as well as some basic encryption algorithm design principles.

• Theoretical versus Practical Security

  This chapter introduces the idea that unbreakable cryptosystems exist but are not practical in the real world. It also points out that most practical cryptosystems are breakable in theory. The real world is always about compromise. We argue that the study of cryptography is essentially the study of a toolkit of cryptographic primitives that can be assembled in different ways in order to achieve different security goals.

  Note: The first three chapters basically provide the fundamental background needed for cryptography.

• Symmetric Encryption

  This chapter starts with a discussion about the provision of confidentiality. There are two types of cryptosystem, and we’ll look at the first of these, symmetric encryption, with respect to providing confidentiality. This chapter also discusses the different types of symmetric encryption algorithms as well as the different ways in which they can be used.

• Public-Key Encryption

  This chapter introduces the concept of public-key encryption. It explains the reasons for using public-key encryption and discusses two important public-key cryptosystems in some detail.

• Data Integrity

  This chapter introduces the kind of symmetric cryptography that can be used to provide data integrity and stronger data origin authentication.

• Digital Signature Schemes

  This chapter outlines cryptographic techniques that provide non-repudiation.

• Entity Authentication

  This chapter explains how cryptography can be used to provide entity authentication. It also considers random number generation, which is often required for entity authentication mechanisms.

• Cryptographic Protocols

  This chapter explains how these cryptographic primitives can be combined to form cryptographic protocols.

  Note: The chapters mentioned above explore the various components that make up the cryptographic toolkit. This includes cryptographic primitives and the cryptographic protocols that combine them.

• Key Management

  This chapter discusses the concept of key management in general terms, focusing on the management of secret keys. It studies the life cycle of a cryptographic key and discusses some of the most common techniques for conducting the various phases of this life cycle.

• Public-Key Management

  This chapter introduces the issues of key management, particularly as it relates to public-key cryptography. Key management is arguably the most important and often overlooked area of cryptography from a practical perspective. It underpins the security of any cryptographic system and is the aspect of cryptography where practitioners are most likely to become involved in decision-making.

  Note: In the chapters named above, we explore what is arguably the most important, and often overlooked, area of cryptography from a practical perspective: key management. This underpins the security of any cryptographic system and is the aspect of cryptography where users and practitioners are most likely to become involved in decisions concerning cryptography.

• Cryptographic Applications

  This chapter reinforces the lessons from the previous chapters by looking at some applications of cryptography in detail. Since many of the issues raised in the previous chapters require application-dependent decisions to be made before cryptography can be implemented, we demonstrate how several important applications of cryptography actually address these issues. In particular, we discuss why particular cryptographic primitives are used and how key management is conducted.

• Cryptography for Personal Devices

  This chapter talks about how users often inadvertently use cryptography when securing their personal devices and communications.

• Control of Cryptography:

  This chapter looks at wider societal issues raised through the use of cryptography and considers strategies for balancing privacy and control.

  Note: The final three chapters explore the usage of cryptography and some predicaments that come along with cryptography.

Additional materials

This course also offers the following additional features:

• Further reading: Each chapter includes a brief summary of resources that can be used to further pursue the topics discussed. These are only intended to be starting points and are by no means comprehensive. These resources are normally a mix of accessible reading, important research articles, relevant standards, and useful web links. Carefully directed web searches should also prove an effective means of finding further information.

• Quizzes: Each chapter contains quiz questions designed to enhance the understanding of the chapter contents.

• Mathematics Appendix: Finally, there is a short appendix at the end of the course that contains some elementary background mathematics that complement the contents of this course. This appendix is intended for those who want to learn about the mathematical aspects of cryptography and is optional reading for the completion of this course.