Milestone: 100M Certificates Issued
I still wonder how Let&#x27;s Encrypt works.<p>I understand that the problem they solve: A user wants to get the public key for a certain domain. So he knows he is talking to a server by the domain owner and not some man in the middle.<p>So he asks a third party whos public key he already has. In this case Let&#x27;s Encrypt. Ok.<p>But how did Let&#x27;s Encrypt get the public key from the domain owner?<p>I know they make the domain owner install some software on his server. But how does that make sure they talk to a server by the domain owner and not a man in the middle? Does the software include some private key so they can send them a &quot;hey, encrypt this&quot; message and to prove the server in fact has that private key?<p>If so, why is the Let&#x27;s Encrypt software so complicated and not just a 5 line script or something?