PKI Overview

Introduction to PKI

PKI provides a way of verifying the identity of a remote site by using a digital certificate. PKI uses a CA to validate and digitally sign your information. This process ensures that neither your information nor the signature can be modified. Once you sign your information, the information becomes a digital certificate. Devices that receive a digital certificate verify the certificate’s information by validating the signature with public key cryptography.

The PKI consists of the following components for managing digital certificates:

• RA: Verifies the identities of entities, authorizes their certificate requests,and generates unique asymmetric keypair (unless the users’ certificate requests already contain public keys).

• CA: Issues corresponding digital certificates for the requesting entities.

• CRL: Identifies the certificates that are no longer valid. Each entity possessing the authentic public key of a CA can verify the issued certificates.

How PKI Works

PKI supports the distribution and identification of public encryption keys, enabling users to both securely exchange data over networks such as the Internet and verify the identity of the other party.

Figure 1 shows how the authentication happens between two users using the public and private key.

Figure 1: Public Key Infrastructure

Benefits of PKI

• Enhanced security: PKI provides robust security by using asymmetric cryptography, which is more secure than symmetric cryptography. The use of public and private keys ensures that data encrypted with a public key can only be decrypted with the corresponding private key.
• Trust hierarchy: PKI establishes a trust hierarchy through the use of CAs, RAs, and Certificate Repositories. This hierarchy ensures that all entities within the network trust each other based on their certificates and the CA that issued them.
• Data integrity: Digital certificates issued by PKI ensure the integrity of data by providing a way to verify the authenticity of the sender and the data itself. This authenticity verification prevents tampering or alteration of data during transmission.
• Scalability: PKI is scalable and can be used in large networks with multiple entities. It supports various standards like X.509 and Public Key Cryptography Standards (PKCS), making it versatile and adaptable to different network configurations.
• Ease of management: While setting up a PKI requires some initial configuration, it simplifies the management of digital certificates and keys. This makes it easier to manage and maintain secure connections across the network.

PKI Terminology