A public key infrastructure (PKI) includes systems, software, and communication protocols that distribute, manage, and control public-key cryptography. A PKI publishes digital certificates. Because a PKI establishes trust within an environment, a PKI can certify that a public key is tied to an entity and verify that a public key is valid. Public keys are published through digital certificates.
In this section, we discuss key PKI components as well as a few other PKI concepts.
Security professionals should understand the certificate life cycle. Refer to below figure for complete lifecycle.
So, How does a User/Client request for a Digital Certificate in reality?
If once it receive this certificate; How does it interact with the other entities?
Refer to below figure to get a Clear understanding of these questions!
A discussion of cryptography would be incomplete without coverage of key management practices.