What Is PKI (Public Key Infrastructure)

PKI Certificate Tutorials - Herong's Tutorial Examples

∟Introduction of PKI (Public Key Infrastructure)

∟What Is PKI (Public Key Infrastructure)

This section describes what is PKI (Public Key Infrastructure) - an information technology infrastructure that enables Internet users to securely exchange information using the public and private key technology.

What Is PKI (Public Key Infrastructure)? PKI is an information technology infrastructure that enables Internet users to securely and privately exchange information through the use of a public and a private key pair that is obtained and shared through a trusted authority. The public key infrastructure provides digital certificates that can identify individuals or organizations, and directory services that can store and, when necessary, revoke the certificates.

Main elements of PKI are:

A public and private key encryption technology that can be used to encrypt and decrypt information.
Subjects (users, organizations, or systems) who wants to use the public and private key technology to exchange information securely.
A registration authority (RA) that verifies subject's identity.
A certificate authority (CA) that issues the digital certificate binding subject's identity with subject's public key.
A validation authority (VA) that verifies the digital certificate of a subject.
A certificate revocation list (CRL) that contains certificates revoked by the CA.

The following diagram from wikipedia.org provides a good illustration of how PKI works:

Here is how to read the diagram:

A user applies for a certificate with his public key at a registration authority (RA).
The RA confirms the user's identity to the certification authority (CA).
The CA issues issues a certificate signed by the CA to the user.
The user can then digitally sign a commercial contract using his/her certificate.
Other parties of the contract can check user's identity with a validation authority (VA).
The VA verifies user's identity with the CA and sends back confirmation to contract parties.

Note that signing commerical contracts is just one use case of the PKI technology. There are many other use cases that are not shown in the above diagram. See next tutorial for more examples.

Table of Contents

About This Book

►Introduction of PKI (Public Key Infrastructure)

►What Is PKI (Public Key Infrastructure)

Usage Examples of Public Key Infrastructure