Authentication Methods used by SSH

SSH (Secure Shell) is a network protocol that allows secure communication between two computers. It provides a secure way of logging into a remote machine and executing commands. SSH uses various authentication methods to establish a secure connection between the client and the server. Some of the authentication methods used by SSH are:

1. Public-key authentication:

Public-key authentication is a method of authentication that uses a public and private key pair. The client generates a public and private key pair and sends the public key to the server. The server stores the public key in a file, and the client uses the private key to authenticate itself to the server. This method is more secure than password authentication because the private key is never transmitted over the network.

2. Host-based authentication:

Host-based authentication is a method of authentication that uses the client's host name and IP address to authenticate it to the server. The server checks the client's host name and IP address against a list of trusted hosts, and if it matches, the client is allowed to connect. This method is less secure than public-key authentication because it relies on the trustworthiness of the client's host.

3. Password authentication:

Password authentication is a method of authentication that uses a username and password to authenticate the client to the server. The client sends its username and password to the server, and the server checks them against a list of valid usernames and passwords. This method is less secure than public-key authentication because passwords can be easily guessed or intercepted.

All of the mentioned authentication methods are used by SSH. SSH supports these methods to provide a secure connection between the client and the server. The choice of authentication method depends on the security requirements of the system and the level of trust between the client and the server.