Step1: Install SSH server

1. Login to your server

2. install ssh server

   sudo apt-get install openssh-server
   

3. Make sure service is started

   systemctl status ssh
   

Step2: Generate public and private key

1. Download ssh tools MobaXterm or Putty
   • MobaXterm Download (Recommended)
   • Putty MSI Download
2. Generate key
   • MobaXterm: Tools > MobaXterm SSH Key Generator > Generate
   • PuTTygen: Generate
3. Save private key file
4. Copy public key in text box

Step3: Add public key to your server

1. Edit key file

   nano ~/.ssh/authorized_keys
   

2. Paste your public key

Step4: Config authentication method

1. open file config

sudo nano /etc/ssh/sshd_config

2. change some config

PubkeyAuthentication yes
PasswordAuthentication no

3. restart ssh

sudo systemctl restart ssh

Step5: Test Authen with public key

1. open mobaXterm
2. Session > SSH
   • Remote host: host ip
   • Specific username: username
   • Advanced SSH settings: Use private key > Select private file
3. OK

Reference

• How to Add SSH Public Key to Server
• How to Set Up SSH Keys on Ubuntu 20.04