[Python.NET] token based security, ssl certificate and https, proxy

I have developed a new web service.   Now, I need to deal with security issue as we are intending to make it a secure service.   In order to set up SSL and https, I need to obtain and install an SSL certificate.  Who is the certificate authority?   Do you know how to go about with this?   Are there concise articles on this?   Regards.   David