 Hello, my name is Hisham. I'm from Justice and Peace and welcome to this tutorial in which we are going to talk about PGP encryption as a method to secure your email communications. We are going to do this in two parts. This first part is about how PGP works and in the second part we will see how you can use it in practice. Now let's imagine that a person A wants to communicate safely via email with a person B. They want to make sure that nobody apart from both of them can read the content of their emails. Nobody unauthorized like a government, their ISP, maybe their phone company, any healthcare out there, Google for that matter, Microsoft and so on and so forth. Luckily for both of them there is a free technology called PGP encryption that would allow them to do just that. So let's see how PGP encryption works. So to allow person B to write back to her, person A had a great idea. She decided to buy a padlock and as you know padlocks come with a specific key. It is presumably the only key in the world that can open this particular padlock. In PGP encryption jargon this is called a key pair. The padlock is known as the public key although key here is a bit of a misnomer but it should be understood as the padlock. It's called the public key and the key itself is called the private key. Person A then decides to send her public key to person B so that person B can write a letter or put whatever content he wants to send back to person A into a box, lock that box with the padlock, belong into A and send it back to her via the internet in a safe way. And of course the same works the other way around. If person B wants person A to write back to him he needs to acquire a padlock that he alone has the key to unlock. He then sends that padlock to person A and person A puts whatever content she wants to send back to person B into a box that she locks down with the padlock belonging to B. We force send in the whole thing via the internet. Now provided that A's computer and B's computer are not infected in other words there is nobody looking over their shoulder for anybody standing in the middle they can still know that A and B are communicating but they cannot possibly know what they are communicating about unless they have the private key of either A or B. So it is very important for both A and B to keep their private key safe that they do not share it publicly. The public key on the other hand needs to be shared widely as we saw person A needed to share her public key or padlock with person B before she could receive an encrypted email from person B. But what if someone in the public wants to write an encrypted email to person A? Maybe person A doesn't know who that person is. Maybe person A is a journalist and she's hoping that a source might want to write something important back to her. So she needs to find a way to publicize her public key. In order to do so person A needs to do two things. First of all she needs to publish her public key into what is known as public key repositories or key servers. These are online databases that are maintained by a couple of organizations that people can consult and then they can search for person A's key and then write an encrypted email back to her. Now you may ask yourself what if someone tries to impersonate person A? Couldn't they publish a fake padlock or fake public key into one of those online key servers? That is indeed a possibility. That is why it is not enough to publish your public key into one of those online key servers. It is very wise to also offer a way for the public to verify that you are the real holder of that public key and that you are the only person with the private key capable of unlocking any email that has been encrypted using that particular public key. And there are many ways to do so. One of them would be to identify your public key in your email signature. Another way would be to publicize your public key onto your website or to identify your public key in your social media bio or to also identify your public key on your business cards. So that's it for the theoretical part of PGP encryption. Don't worry, although this looks a bit complicated. In practice it's very easy to use and that's what we are going to talk about in part two of PGP encryption. Make sure to watch that video. Thank you for watching.