for automatic generation of certificate use:
openssl req -x509 -newkey rsa:2048 -keyout ~/.3dprinteros/private_key.pem -out ~/.3dprinteros/certificate.pem -days 10000 -nodes -subj "/C=US/ST=California/L=San Francisco/O=3D Control Systems/OU=3DPrinterOS/CN=3dprinteros.com"
