Synology DSM Login SSH With ECC Certificate

Generate ECC Certificate

ssh-keygen -t ed25519
cd /var/services/homes/$USER/.ssh && cp id_ed25519.pub authorized_keys
sudo chmod 700 /var/services/homes/$USER/.ssh
sudo chmod 644 /var/services/homes/$USER/.ssh/*

Disable SSH Password Authorization

sudo sed 's/PasswordAuthentication yes/PasswordAuthentication no/g' /etc/ssh/sshd_config

Restart SSH Service

sudo systemctl restart sshd

The Private Key

cat /var/services/homes/$USER/.ssh/id_ed25519