Create SSL Certificate

create_ssl_certificate

# First create the SSL certificate (.crt file)
# See: https://www.digitalocean.com/community/tutorials/how-to-create-a-self-signed-ssl-certificate-for-apache-in-ubuntu-16-04
sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/ssl/private/apache-selfsigned.key -out /etc/ssl/certs/apache-selfsigned.crt

# Then generate the .pfx file
# See: https://www.ssl.com/how-to/create-a-pfx-p12-certificate-file-using-openssl/
openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt

# This output file is what you use for the digital signature.
# Cheers.