I have been using GPG for a long time, but I never got around to setting it up in Apple Mail. There was always something more important. But recently, I finally did it. The main problem was that I couldn’t find a suitable solution for iOS. I haven’t solved this issue yet, but if I need to work with constantly encrypted content, I would rather use ProtonMail or Tutanota.

So, PGP allows you to sign and encrypt a message. The signature ensures that the message has not been altered after it was signed by the sender. Encryption ensures that the message will not be read by third parties. Signature and encryption can be used together or separately. I always enable the signature, and encryption only when necessary.

The main security issue in the modern world is identification. How can we be sure that the person we are corresponding with or exchanging files with is really who they claim to be? How can we be sure that the files we receive have not been altered along the way? How can we be sure that the files we receive were actually sent by the person who sent them?

These questions are solved by signing the data being transmitted. A signature is some information that is generated using a private key and can be verified using a public key. If the signature is correct, then the data has not been altered in transit and it was sent by the person who sent and signed it.