One of the most common mistakes in CISSP and CC exams:

• Confusing PKI with encryption.

PKI uses encryption. But encryption is not its purpose.

PKI solves one problem: how do you verify that someone is who they claim to be?

Encryption solves a different problem: how do you hide data from people who should not see it?

Two different problems. Two different solutions.

One article that explains both the difference and why it matters for the exam.