Match RSA private key to Certificate

Step One

Run the following command on the key file to determine the modulus: openssl rsa -noout -text -in secure.server.com.pem

Example Output

Private-Key: (1024 bit)
modulus:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
    00:00:00:00:00:00:00:00:00
    ...

Step Two

Run the following command on the certificate file to match the modulus: openssl x509 -noout -text -in secure.server.com.pem

Example Output

...
            RSA Public Key: (1024 bit)
                Modulus (1024 bit):
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:
                    00:00:00:00:00:00:00:00:00
    ...

If they match the certificate and key match.