Lesson video

Hello, my name is Mrs. Holborow and welcome to Computing.

I'm so pleased that you've decided to join me for the lesson Today.

In today's lesson, we'll be learning about encryption and some common uses of encryption that are used to protect communication.

Welcome to today's lesson from the unit, Cyber threats and security.

This lesson is called Encryption Tools to Protect Communication, and by the end of today's lesson, you'll be able to describe and explain applications of encryption.

Shall we make a start? We will be exploring these keywords throughout today's lesson.

Encryption.

Encryption, the process of converting information or data into an unreadable format called ciphertext, using an algorithm and key.

Key.

Key, a piece of information that is used by an encryption algorithm to lock or unlock a message or data.

Cypher.

Cypher, a method or algorithm used to encrypt and decrypt information.

Look out for these keywords throughout today's lesson.

Today's lesson is broken down into two parts.

We'll start by describing encryption.

We'll then move on to explain applications of encryption.

Let's make a start by describing encryption.

Encryption is the process of encoding data or a message so that it cannot be understood by anyone other than the intended recipient.

Encryption is used as a security measure to protect information from being read or tampered with by others.

To encrypt data or information, an encryption algorithm is used.

An encryption algorithm is a set of rules that transforms readable data called plaintext into unreadable data called ciphertext.

Plaintext is the original readable version of a message or data before it has been encrypted.

The meaning of the text or data can be easily understood by anyone who sees it, which is why it needs encryption to keep it private.

Ciphertext is the scrambled unreadable version of a message or data that has been encrypted using an algorithm.

It looks like random letters, numbers, or symbols, and can only be understood if it is decrypted.

Time to check your understanding.

The original readable version of data is known as A, plaintext, B, ciphertext, or C, encrypted text.

Pause the video whilst you have a think about the answer.

Did you select A, plaintext? Well done.

Remember, this is the version of the data or message before it has been encrypted.

The opposite of encryption is decryption.

Decryption is the process of converting ciphertext that is encrypted and unreadable back into readable plaintext so that the intended recipient can access the data.

When data is encrypted with an algorithm, an encryption key is generated.

The encryption key contains information about how the data has been transformed into an unreadable format and how it can be transformed back into its original readable format.

Without the key, it's extremely difficult to decrypt scrambled data.

Encrypting data with a key ensures that only someone with the correct key can decode and understand the original information.

This is why encryption can be a very effective method to protect data and information.

A method or algorithm used to encrypt and decrypt information is known as a cypher.

Cyphers have been used to protect data for thousands of years, well before modern digital computers were developed.

The Caesar Cypher is named after Julius Caesar, who reportedly used it to communicate with his generals.

The Caesar Cypher is one of the simplest and earliest known methods of encryption and is thought to be over 2,000 years old.

The Caesar Cypher encryption method is a type of substitution cypher.

A substitution cypher is where each letter in the original message is replaced by a letter in a fixed number of positions down the alphabet.

Caesar was known for using an encryption key of plus three, in which A becomes D.

The Caesar Cypher key is a very simple version of an encryption key, but it is still a key.

In modern times, substitution cyphers are a very weak form of encryption and can be easily broken.

Today, there are two main types of encryption, symmetric encryption and asymmetric encryption.

Let's have a look at each one of those now.

Symmetric encryption uses a single secret key that can be used to both encrypt and decrypt data.

The same key must be known by both the sender and the receiver of the encrypted data.

A big challenge with symmetric encryption is ensuring the secret key is distributed and managed securely.

Asymmetric encryption uses a pair of related but different keys.

A public key is freely distributed and can be used by anyone to encrypt data intended for the owner of the key pair.

A private key is kept secret by the owner and is required to decrypt data that was encrypted with the corresponding public key.

Note that there are many different types of encryption algorithms and each will use its own method of scrambling data.

Each encryption algorithm may be used in different situations depending on the level of security needed.

Time to check your understanding.

Which type of encryption uses a public and private key? Is it A, substitution, B, symmetric, or C, asymmetric? Pause the video whilst you have a think about your answer.

Did you select C, asymmetric? Remember, we're talking about a pair of keys here.

Well done.

True or false? Symmetric encryption uses a single secret key.

Pause the video whilst you have a think.

Did you select true? Well done.

Symmetric encryption uses a single secret key.

Okay, we're moving on to our first task of today's lesson.

For part one, I'd like you to write two to three sentences to describe encryption, and then for part two, I'd like you to describe the difference between symmetric and asymmetric encryption.

Pause the video whilst you have a go at the tasks.

How did you get on with the tasks? You're doing a brilliant job so far, so well done.

Let's have a look at some sample answers together.

For part one, you were asked to write two to three sentences to describe encryption.

Encryption is the process of encoding data or a message so that it cannot be understood by anyone except the intended recipient.

Readable information is called plaintext, and encryption transforms it into an unreadable form called ciphertext.

A specific key is required to decode the ciphertext and access the original message, which makes encryption an effective method of securing data.

For part two, you asked to describe the difference between symmetric and asymmetric encryption.

Symmetric encryption uses a single secret key that is used to both encrypt and decrypt data.

Whereas asymmetric encryption uses a pair of related, but different secret keys called a public key and a private key.

Okay, so we've described encryption, but let's now move on to explain applications of encryption.

Encryption is used to keep our personal and sensitive information safe when we use real world technologies such as websites, messaging apps, and online services.

It can be used to protect things like passwords, credit card numbers, messages, and health records.

Encryption is important to these technologies because it protects privacy, secures data, and helps prevent cyber attacks.

Without encryption, private data would be freely accessible and exploitable.

Messaging apps use end-to-end encryption, meaning even the app company can't read your messages.

With end-to-end encryption only you and the person you're messaging have the private key needed to read the messages.

Websites use encryption to establish a secure and private connection between the user's browser and the web server.

Encryption scrambles user data that is sent and received, so even if someone intercepts it in between, they can't read or misuse it without the proper decryption key.

You can tell a website uses encryption when you see that the URL begins with HTTPS and a padlock icon appears in the browser address bar.

Time to check your understanding.

What icon is commonly found in the browser address bar when a website uses encryption? Is it A, a tick, B, a padlock, or C, a smiley? Pause the video whilst you have a think.

Did you select B, a padlock? Yes, well done.

And remember, the URL will typically start with HTTPS.

When encryption is used, only the user's browser and the website server have the keys to decrypt the information.

Encryption ensures that even if a third party intercepts the data being transmitted, they will only see jumbled unreadable ciphertext.

Online banking services use multiple levels of encryption to ensure the highest level of security for sensitive financial data.

Banking websites, portals, and apps are encrypted along with any data that is stored on their servers.

Multiple layers of encryption ensure that even if one layer of data is compromised, the data remains secure.

Cloud storage uses encryption to protect files and data from unauthorised access while data is stored online and when it's being uploaded.

Using encryption in cloud storage keeps files safe even if the servers are hacked and security is compromised.

Gaming platforms use encryption to protect user data.

Secure online payments, keep in-game communications private, and prevent cheating or tampering with game files.

Encryption in gaming helps keep the experience safe, fair, and private for players.

Time to check your understanding.

True or false? Banking services only use one layer of encryption.

Pause the video whilst you have a think.

Did you say false? Yes.

Well done.

Banking services use multiple levels of encryption to ensure the highest level of security for sensitive financial data.

Encrypted unreadable data is known as A, ciphertext, B, plaintext, or C, decrypted text.

Pause the video whilst you have a think.

Did you select A, ciphertext? Well done.

Okay, we're moving on to our final set of tasks for today's lesson and you've done a fantastic job so far, so well done.

Aisha says, "I found a really good website for games, Jun." But Jun says, "I don't think we should use that website, Aisha.

I don't think it uses encryption." For part one, look at the webpage above and describe why Jun thinks it isn't secure and doesn't use encryption.

And then for part two, explain why encryption is used on websites.

Pause the video here whilst you complete the activity.

How did you get on with the activities? Well done.

Let's have a look at some sample answers together.

For part one, you were asked to look at the webpage and describe why Jun thinks it isn't secure and doesn't use encryption.

Jun has noticed that the URL in the browser starts with HTTP and not HTTPS.

This means that the website is not secured with encryption.

He might have also noticed that there is no padlock icon in the browser.

The padlock also means that the website is secure.

For part two, you asked to explain why encryption is used on websites.

Websites use encryption to establish a secure and private connection between the user's browser and the web server.

Encryption scrambles user data as it is sent and received, so even if someone intercepts it, they can't read or misuse it without the proper decryption key.

This improves security and helps protect private user details.

Okay, we've come to the end of today's lesson, Encryption Tools to Protect Communication.

You've done a fantastic job so far, so well done.

Let's summarise what we've learned together in this lesson.

Encryption is the process of encoding data so that it cannot be understood by anyone other than the intended recipient.

Encryption is used to keep our personal and sensitive information safe when we use real world technologies such as websites, messaging apps, and online services.

Encryption, protects personal data, keeps messages private, and ensures security during online transactions.

I hope you've enjoyed today's lesson, and I hope you'll join me again soon.

Bye.