As we all know, SSH, also known as Secure Shell, is the cryptographic network protocol that allows you to securely communicate/access a remote system over unsecured network, for example Internet. Whenever you send a data over an unsecured network using SSH, the data will be automatically encrypted in the source system, and decrypted in the destination side. SSH provides four authentication methods namely password-based authentication, key-based authentication, Host-based authentication, and Keyboard authentication. The most commonly used authentication methods are password-based and key-based authentication.