The private key should be kept private (hence the name) anybody who has the private key can impersonate the person who generated it and steal their private information. Not only do SSH keys help to protect your data, they add convenience. This checking continues as information is sent to you from the server.
So when you connect to the remote server, the server confirms your identity by seeing if your private key unlocks the lock. The public key is like a lock, anybody can see it but only the person with the private key can unlock it.
SSH secures information with the use of a private and public key. The Secure SHell (SSH) protocol is used to securely access remote servers.
