SSL certificates increase security for your Droplet and your users by enabling encrypted connections to your server. You can purchase certificates through a commercial SSL certificate authority or use an open source certificate authority like Let’s Encrypt.
Commercial SSL certificates usually cost money and remain valid for one year or longer. You can acquire a commercial SSL certificate and install it on an nginx or Apache web server running on your Droplet.
Let’s Encrypt provides free SSL certificates that remain valid for three months but can be automatically renewed. An important difference between Let’s Encrypt SSL certificates and commercial certificates is that Let’s Encrypt certificates can only be installed after your domain name publicly points to the IP address of your Droplet.