About This Course

Get an introduction to cryptography, and explore the prerequisites and the intended audience for this course.

What is cryptography?

Cryptography is a subject with relevance to our everyday life that has undergone a dramatic transformation. Cryptography used to manifest itself in the public imagination through its historical use, primarily to protect military communications and through recreational puzzles. However, largely due to the development of computer networks, particularly the internet, most of us now use cryptography on a daily basis.

Cryptography is fundamental to the wider notion of information security. Electronic information can easily be transmitted and stored in relatively insecure environments. This has resulted in fundamental changes to the risks to which information is exposed. As the financial impact of information security incidents rises, so does the need for information security protection and control.

Cryptography is a vital technology that underpins many of these controls. It provides a suite of basic mechanisms for implementing the security services that protect electronic information, such as confidentiality, data integrity, and authentication, also known as the CIACIA triad.

Cryptography doesn’t secure information on its own, but many technical mechanisms for protecting information have cryptography at their core. That’s why cryptography is an important subject for anyone with an interest in information security. There are also other reasons for the wide interest in cryptography as a subject, including the following:

  • Cryptography plays an interesting political role. It’s a key technology during times of conflict. Its modern use presents society with several intriguing moral and political dilemmas.
  • Cryptography has a wide intrinsic appeal to the general public. Many people are fascinated by secrets and codes. This has been successfully exploited by the mainstream media.

Why should you choose this course?

There are many books and courses about cryptography. What distinguishes the approach taken in this course is a combination of the following factors:

  • Fundamental principles: This course is intended to be both relevant and relatively timeless. It’s easy to write a cryptography book or course that becomes out of date quickly. This course is intended to be just as relevant in ten years’ time as it would have been ten years ago. We achieve this by concerning ourselves primarily with the fundamental principles rather than the technical details of the current technology.
  • Application-focused: This course is primarily concerned with the parts of cryptography that a user or practitioner of information security needs to know. While there is a great deal of contemporary theoretical research on cryptography, few of these ideas make it through to real-world applications, which tend to deploy only well-tested and understood techniques. This course focuses on cryptography for everyday applications.
  • Widely accessible: This course is intended to be suitable as a first read on cryptography. It focuses on core issues and provides an exposition of the fundamentals of cryptography.
  • Contextual relevance: This course focuses on cryptography as an underlying technology supporting information security in today’s context rather than a topic in its own right.

Note: This course deliberately doesn’t concentrate on the mathematical techniques underpinning cryptographic mechanisms. This course is intended to be introductory, self-contained, and widely accessible.


In this course, you’ll learn why cryptography is important, how it can be used, and what the main issues are regarding its implementation. You don’t need to have any prior knowledge of cryptography to benefit from this course. You also need almost no prior knowledge of mathematics. All you need is a desire to learn about cryptography. That is enough to make you eligible to take this course!

Who should read this course?

The primary intended audiences are listed below.

Users and practitioners of information security

Cryptography is a subject of relevance to anyone who needs to secure digital data. This course is intended to be of interest to:

  • Information technology professionals who need to apply security techniques to data.
  • Information security professionals whose role is to protect information.
  • Managers of organizations who want to learn about the different issues concerning data security.
  • General users of information technology who want to understand how to protect their data.

Students of cryptography

This course may also be of interest to students studying the mathematics of cryptography since it complements more mathematical treatises by providing a kind of bridge between the theory of cryptography and the real-world problems it attempts to solve. For students who already know the how, this course will explain the why.

General interest audience

This course has also been written in order to appeal to a general science or engineering audience who seeks a greater understanding of what cryptography is and how it works.