SSH Public Key Authentication

Generating Keys 

To generate the public and private key files, you can use ssh-keygen command which is installed with OpenSSH.

ssh-keygen

By default, your public key file is located at ~/.ssh/id_rsa.pub and it can be shared with anyone. Your private key file is located at ~/.ssh/id_rsa and it must be kept secret.

Key Installation 

You now need to copy your public key file to the remote host(s) that you want to be able to use public key authentication.
1. Copy your public key to remote host1.example.net using one simple command:

ssh-copy-id -i ~/.ssh/id_rsa.pub username@host1.example.net

2. Manual Installation
To install the key manually you need to append the key to the ~/.ssh/authorized_keys file on each host you wish to use.

# copy the key to the remote host
scp ~/.ssh/id_rsa.pub user@remotehost:id_rsa.pub
# ssh into the remote host using your password
ssh user@remotehost
# append the public key
cat id_rsa.pub >> ~/.ssh/authorized_keys
rm id_rsa.pub

ON WINDOWS You can download puttygen.exe to generate private and public key pairs. Copy public keys generated to your remote host ~/.ssh/authorized_keys file and make sure they are in ONE LINE.