Simple ciphers: Substitution ciphers
The Caesar cipher is a form of substitution cipher, so called because each letter is substituted for another. There are other types of cipher which we will focus on a …
Course: An Introduction to Cryptography
What is a ‘simple cipher’?
A cipher is a method used to encrypt or encode a message in order to make it unreadable by unauthorised parties. Ciphers have been used throughout history to protect sensitive …
Rivest–Shamir–Adleman (RSA) encryption
Rivest-Shamir-Adleman (RSA) encryption is a popular and widely used public-key cryptography algorithm named after its inventors Ron Rivest, Adi Shamir, and Leonard Adleman. It’s used for secure communication over the …
Activity 2: Overview
In last activity we learned about what cryptography is and what it is used for. In this activity we will introduce some historic ciphers which are great fun to learn …
Activity 1: Summary and next steps
In this activity we have looked at what cryptography is and the three main reasons it is used in modern life. To give you an idea of what cryptography looks …
The three roles of cryptography
In the last step, we introduced that there are three ways in which cryptography contributes to protecting data. Here we look at these in more detail: Privacy: cryptography helps ensure …
Modern day cryptography
The two types of modern cryptography There are two main types of modern cryptography; private key cryptography and public key cryptography. We will look at each of them in more …
An introduction to simple cryptography
In 2021, Facebook reported that over 100 billion messages were sent on its platforms every day, including Facebook Messenger, WhatsApp, and Instagram Direct. All of these messages are private between …
Activity 1: Overview
In this activity, we will introduce what cryptography is and how it plays a massive role in modern day life. You will learn that cryptography is not a new concept, …
What do we use cryptography for now?
As you have learned, cryptography is the practice of securing information by converting it into a code that is unreadable without the proper decryption key. Cryptography has been used throughout …
Activity 3: Overview
Last week you learned about some of the history of cryptography and how to encrypt and decrypt messages using some of the oldest cryptographic techniques. Whilst these techniques are interesting …
Welcome to “An introduction to cryptography”
Welcome to the thrilling world of cryptography! Cryptography is the exciting world of secret codes and encrypted messages. It’s like a puzzle that keeps your mind sharp and your information …
Further exploration
For those of you learning with Click Start, do go back to the Click Start page and look up the other courses on offer. If you are interested in cryptography …
Activity 2: Summary and next steps
In this activity you learned about four kinds of ciphers (substitution, transposition, permutation and polygraphic ciphers) and you had a go at encrypting and decrypting data manually. This is normally …
Course summary
In this video, Sam provides a summary of what you have learned about on this course. Reflect and share Choose one or two of the following questions to reflect on: …