A key pair is generated consisting of a public and private key. Key-based authentication, on the other hand, uses cryptography to ensure secure connections. This has the advantage of being easier to set up but suffers security-wise due to being prone to brute-forcing and password guessing. The standard way of connecting to a machine via SSH uses password-based authentication. But even that isn't bulletproof since SSH private key passwords can be cracked using John the Ripper. Key-based authentication is much more secure, and private keys can even be encrypted for additional security. However, SSH is prone to password brute-forcing. Secure Shell is one of the most common network protocols, typically used to manage remote machines through an encrypted connection.
