Now, we move on to creating a private Certificate Authority (CA). First, some explanation. The CA is used in SSL to verify the authenticity of a given certificate. The CA acts as a trusted third party who has authenticated the user of the signed certificate as being who they say. The certificate is signed by the CA, and if the client trusts the CA, it will trust your certificate. For use within your organization, a private CA will probably serve your needs. However, if you intend use your certificates for a public service, you should probably obtain a certificate from a known CA.