Answers and Explanations

1. A CA has a root certificate, which it uses to sign keys.
2. I would use a private CA for internal use only; these certificates will not be accepted outside of your organization.
3. I would use a public CA for B2B activities.
4. If you were a military, security, or banking organization, you would keep the CA offline when it is not being used to prevent it from being compromised.
5. An architect would build the CA or intermediary authorities.
6. The CA would sign the X509 certificates.
7. Certificate pinning can be used to prevent a CA from being compromised and fraudulent certificates being issued.
8. If two separate PKI entities want to set up a cross certification, the root CAs would set up a trust model between themselves, known as a bridge trust model.
9. PGP uses a trust model known as a web of trust.
10. A Certificate Revocation List (CRL) is used to determine whether a certificate...