Pretty Good Privacy

Pretty Good Privacy:

Pretty Good Privacy (PGP) is an encryption program that provides cryptographic privacy and authentication for data communication. PGP is used for signing, encrypting, and decrypting texts, e-mails, files, directories, and whole disk partitions and to increase the security of e-mail communications.

How PGP Works?

PGP is very easy to understand, on the surface. Imagine you want to send your credit card information to a friend and you write it on a piece of paper. You then put the paper in a box and send it by mail.

A thief can easily steal the box and look at the paper that contains your credit card information. What could you do instead?

You decide to put a key lock on the box, but you realize that you have to send the key along with the box. That’s no good.

What if you meet your friend in person to share the key beforehand? That could work, right? It could, but then both of you have a key that allows to unlock the box. You, as the sender, will never need to open the box again after closing it. By keeping a copy of a key that can unlock the box, you are creating a vulnerability.

Finally, you found just the right solution: you’ll have two keys. The first key will only be able to lock the box. The second key will only be able to open the box. That way, only the person who needs to get the content of the box has the key that allows them to unlock it.

This is how PGP works. You have a public key (to lock/encrypt the message) and a private key (to unlock/decrypt the message). You would send the public key to all your friends so that they can encrypt sensitive messages that they want to send to you. Once you receive an encrypted message, you use your private key to decrypt it.

See this video to be more clear.