Usage Examples of Public Key Infrastructure

PKI Certificate Tutorials - Herong's Tutorial Examples

∟Introduction of PKI (Public Key Infrastructure)

∟Usage Examples of Public Key Infrastructure

This section provides some usage examples of PKI (Public Key Infrastructure), like HTTPS (Hypertext Transfer Protocol Secure) protocol, digital signature, encryption of documents, digital identification.

The most popular usage example of PKI (Public Key Infrastructure) is the HTTPS (Hypertext Transfer Protocol Secure) protocol. HTTPS is a combination of the HTTP (Hypertext Transfer Protocol) and SSL/TLS (Secure Sockets Layer/Transport Layer Security) protocols to provide secure identification of a Website and encrypted communication.

In HTTPS, the Web server's PKI certificate is used by the browser for two purposes:

Validate the identity of the Web server by verify the CA's digital signature in the certificate.
Encrypt a secret key to be securely delivered to the Web server. The secret key will be used to encrypt actual data to be exchanged between the browser and the Web server.

Here is a simple illustration of using PKI in HTTPS communication:

There are 3 major activities illustrated in the diagram:

1. Installing CA (Certificate Authority) root certificate - The browser vendor receives the CA root certificate from the CA, and distributes it as part of the browser installation package.

2. Installing Website certificate - The Website owner sends a certificate request to the CA. The CA, acting as the RA, verifies the Web server identity, and signs (or issues) the Website certificate. The owner then installs the certificate on the Website server.

3.1. Validating Website certificate - An end user visits the Website with the browser and receives a copy of the Website certificate. The browser then acts as the VA and validates it against the pre-installed CA root certificate.

3.2. Securing Website Communications (not shown in the diagram) - If the Website certificate is valid, the browser will use it to share an encryption key with the Website. After that, all communications between the browser and the Website will be encrypted.

Other usage examples of PKI (Public Key Infrastructure) are:

Digital signature - The sender of a digital message uses his/her private key to generate a digital signature attached to the message. The receiver uses the sender's certificate to verify the digital signature to ensure the message was sent by the claimed sender.
Encryption of emails and other documents - The sender of a digital message uses the receiver's certificate to encrypt the message to protect the confidentiality of the message. Only the receiver who can use his/her private key decrypt the message.
Digital identification - User's certificate is stored in a smart card to be used to verify card holder's identities.

Table of Contents

About This Book

►Introduction of PKI (Public Key Infrastructure)

What Is PKI (Public Key Infrastructure)

►Usage Examples of Public Key Infrastructure