Are you planning to take the either the SY0-501 or the SY0-401 version of the Security+ exam?
If so, make sure you understand some basics about certificates, including what they contain.
As an example, see if you can answer this sample Security+ question.
Q. You are examining a certificate received from a web server used for secure transport encryption. Which of the following items will you be able to see in the certificate. (Choose TWO.)
A. The server’s private key
B. The CAs public key
C. The OID
D. The server’s public key
E. The CSR
See if you're correct (and view the full explanation) here.