After we set up an OpenSSH server in the first part and completed the basic configuration to secure the server in the second part of this article series, we now want to configure the server to make use of a key file (hereinafter also “key”) for the login process.
The SSH key authentication is based on the principle of asymmetric encryption. So we need a key pair consisting of a public key and private key. The public key is then stored on the OpenSSH server and the private key goes to the client.
The top priority here is to keep the private key secret forever and in any case. If someone else comes into the possession of the private key, he or she can log on to your server.
As a small obstacle you can provide the private key itself with a password. But nevertheless, if the private key gets public or falls […]