This section still needs to be completed.
Ubuntu has an automated system to download and maintain a list of the most popular public certificates root and chain CA certificates.
It is recommended to use the certs from Ubuntu's repository in /etc/ssl/certs.
However, some operating systems do not have this feature, or for whatever reason you need to manually apply your certificates.
This tutorial covers this scenario.
Download CA Certificates
You may also need the CA's certificates which can be downloaded from StartSSL,
Toolbox, StartCom CA Certificates: Download "StartCom Root CA (PEM encoded)"
It is recommend to change the ca.pem file to include the CA's brand or name, such as, StartSSL_Root_CA.pem.
Download Intermediate Certificates
In some cases you may also need the intermediate certificates.
Toolbox, StartCom CA Certificates: Download "Class 1 Intermediate Server CA"
Change the default sub.class1.server.ca.pem file to include the CA's brand or name such as, StartSSL_Sub_Class1_CA.pem.