Autocrypt makes it easier to communicate end-to-end encrypted via mail. Thhe basic idea is to have a additional mail header "Autocrypt". Within this header you send your gpgkey and your encryption policy. The goal is to have everytime the gpgkeys you need to reply.
They also added a way to transfer your secret gpgkeys between devices.
for sending mails
Autocrypt uses a special header named Autocrypt with the complete keymaterial It is quite straightforward to just add this header to a mail we want to send. With following format:
Autocrypt: email@example.com; prefer-encrypt=mutual; keydata=...
later on we want also add the Autocrypt-Gossip header to support 1:N communication.
for retrieving mails
to make usage of Autocrypt we need to understand the autocypt headers and interpret them correctly. This is a more advanced task, as more parts in KDE PIM needs to been touched. Additionally we need to think about how we dispaly the information to the user. Especially if the keys differ from what we have in the keyring.