Introduction to Encryption

Credits Indira Cornelio, Alma Uguarte Perez Last Updated 2017-06

This introductory session will explain to participants the concept of encryption, as well as a brief overview of the different types of encryption available to users.

ADIDS Element


Parent Topic(s)

Protecting and Encrypting Devices


45-60 minutes

This session was developed for, and should be attributed to, the Institute for War & Peace Reporting resource “Cyberwomen: Holistic Digital Security Training Curriculum for Women Human Rights Defenders” under a Creative Commons Attribution-Share Alike 4.0 International CC BY-SA 4.0 License

Materials to Prepare:

  • Slides (with key points included below)
  • Laptop/Computer and Projector setup
  • Examples of encryption techniques (printed)

Trainer’s Note

This infographic may provide a helpful visual aid for participants during this session (in English):

You may also find the article on Different Types of Encryption from the Security Education Companion to be useful.  

Running the Session:

Part 1 – Have You Used Encryption Before?

Step 1 | Explain that this is an introductory session for encryption as a concept, so you will not yet be going into great depth on any of the encryption tools that participants have likely heard about before (GPG/PGP in particular).

Step 2 | Split participants up into pairs, and then start the session by demonstrating a few examples of encryption techniques. Here are a few examples that you can prepare ahead of time to share with the group:


Each of the letters in the word “Blueprints” is assigned a number:

This is a specific example using a specific word, but can be broadly applied to any number and letter sequence - for instance, if you use the same system as above, the sequence of numbers 8 2 5 7 9 would spell T U R N S when “decrypted”. You could also switch the order of the numbers, so that instead of the above sequence, it now goes:

In this instance, the sequence of numbers 8 2 5 7 9 would now spell L N P U B (which isn’t a word) when “decrypted”; however, you could now “decrypt” the sequence 4 3 2 0 6 as R I N S E.

Old-Fashioned Text Messaging

Use an image of an older-style phone keypad (see below) to demonstrate another kind of “encryption” that participants may be familiar with:

Ask participants how they would use this keypad to spell different words – one example you could use would be to have each participant explain how they would use the keypad to spell their name.

For instance, a participant named Luisa would spell her named by typing the sequence 5 5 5 8 8 4 4 4 7 7 7 7 2.

Step 3 | Once you’ve completed the above examples, ask participants if they have ever used other kinds of encryption – either like the above, or any other examples they can think of (e.g. a common instance of encryption used by many people every day is HTTPS).

Step 4 | Close this part of the session by following-up with another question: What are the common elements they can identify from these different examples of encryption?

Step 5 | Keep in mind that some email services such as Gmail have to be configured to allow the use of Thunderbird as a third party application.

Part 2 – Explaining Encryption

Step 6 | Building on the common elements of encryption identified by participants in Part 1, you should now expand on some further basics and practices for the group:

  • Encryption Methods: Take time to explain how encryption works, referring back to the examples from Part 1 as well as by showing a few example screenshots of what a GPG-encrypted email looks like. Highlight common implementations of encryption – in particular, spend time reviewing HTTPS, end-to-end encryption and GPG/PGP encryption.
  • Keys and Keypairs: Explain how encryption keypairs work, and the algorithmic relationship between public and private keys. Go back through the example implementations previously mentioned (HTTPS, end-to-end and GPG/PGP) and explain for each of these where their respective keys are stored and/or visible to the user.
  • Encryption Practices: Highlight some of the critical best practices associated with common implementations of encryption, such as fingerprint verification and key-signing. To demonstrate, ask participants to locate where within Signal one can verify another user’s fingerprint; similarly, if participants already have GPG/PGP keys you can discuss the benefits and disadvantages of signing and distributing public keys. This is also a good time to discuss end-to-end encrypted messaging for chat apps such as Signal, Telegram and Whatsapp – remind participants that end-to-end encryption on some of these services is not always enabled by default.
  • Encrypted Backups: Building off the GPG/PGP example above, ask participants whether they think it is a good idea to backup their GPG private key, and if so, how might they go about doing so?