What is ssh key authentication in Linux?

SSH key authentication is a secure method of logging into a server using a pair of cryptographic keys. It is commonly used in Linux systems to authenticate users without the need for a password. This method enhances security by using a public-private key pair for authentication, allowing users to log in remotely without transmitting passwords over the network.

How SSH Key Authentication Works

In SSH key authentication, users generate a pair of keys: a public key and a private key. The public key is placed on the server in the 'authorized_keys' file, while the private key remains secure on the user's local machine. When a user attempts to log in, the server challenges the user to prove they have the private key by signing a message, which the server can verify with the public key.

Generating SSH Keys

To generate SSH keys, use the following command in a terminal:

Copying the Public Key to the Server

Once the keys are generated, the public key needs to be copied to the server. This can be accomplished using the following command:

Logging In Using SSH Keys

After the public key is copied to the server, users can log in using the following command: