Openssl

Read a certificate:

openssl x509 -noout -text -in yourcert.cert

The Issuer should be the Certificate Authority. The Subject should represent the organization behind the server.

These commands should match for a certificate/private key pair:

openssl x509 -noout -modulus -in certificate.crt | openssl md5

openssl rsa -noout -modulus -in privateKey.key | openssl md5

Additional wisdom here:

https://www.digitalocean.com/community/tutorials/openssl-essentials-working-with-ssl-certificates-private-keys-and-csrs

http://stackoverflow.com/questions/26191463/ssl-error0b080074x509-certificate-routinesx509-check-private-keykey-values