> A private key is just a very long password that is stored on disk Absolutely 100% not. You're missing the most important aspect of PKI based authentication,

> A private key is just a very long password that is stored on disk Absolutely 100% not. You're missing the most important aspect of PKI based authentication, the asymmetry. With symmetric authentication technologies, like passwords, the only way a user can authenticate is to hand over to the server (which might be malicious) everything that the server needs to impersonate that user. Practically, this means that when I root the Linux server in your environment, and start up 3snake, I'm going to start collecting the passwords of every person who logs in, and I can use those passwords to escalate privileges around the network. This is not even a little bit possible in an environment where SSH key authentication is enforced.