SSL

Self Signed Certificate

Easiest way to create a self-signed certificate for domain.com:

openssl req -subj "/CN=domain.com" -new -newkey rsa:4096 -days 3650 -nodes -x509 -sha512 -keyout private.key -out public.key

If you want to add more domain names, just add more /CN=example.com between the double quotes. The last common name will be the main common name.
Remember: keep your private.key private. Change rights to the file accordingly so that only the application you need it in can read it.