What is Public Key Infrastructure (PKI)?

One of the most important elements of digital encryption and cryptography is the public key infrastructure (PKI), which is an important component of security technology. PKI manages the management and implementation of digital certification and public key encryption by establishing the necessary roles, policies and procedures. This technology can help protect data through a number of components.

This critical element is commonly used to ensure the security of information transmitted over digital channels in several online transactions such as e-commerce, online banking and private email communications. For example, there is one requirement for processes where basic or simple passwords are not strong enough as authentication methods, and provides participants with stronger proof of identity to provide and access transmitted information.

Public key encryption is based on PKI mechanisms, but the term actually refers to a broader system that is itself responsible for verifying authentication attempts and distributing the keys in the first place. However, it should be noted that PKI is not the same as a method of secure data transmission with public key encryption.

How does Public Key Infrastructure (PKI) work?

Many organizations are involved in the PKI development process, and the first step is verification using a digital certificate. First, PKI requires a Registration Authority (RA) to verify the subject. All requirements should also be published along with information about how the PKI was created.

The request is passed from the RA to a Certificate Authority (CA) after successful identity verification, and this organization is tasked with approving, issuing and storing digital certificates. Certificate Authorities with some profile include Comodo, DigiCert, and even GoDaddy. Companies like Let's Encrypt also fall into the category of certificate authorities. These certificates, issued by a certificate authority, are stored in a central hub controlled by management systems that are also tasked with distribution and access.

The CA is responsible for signing and issuing digital certificates as proof that the subject's identity has been verified, and upon an approved RA request, the CA issues a private/public key pair for this.

This may be a simple step in the process, but there are various hardware and software tools running in the background. These include management tasks such as automatic data validation, key pair generation, and request approval. All these elements form a PKI.

Where is Public Key Infrastructure (PKI) used?

Public key infrastructure has applications in a wide range of applications, but is most commonly used to secure digital platforms and services. A common deployment is data transmission security, where information sent over a network can only be viewed by the intended recipient.

PKI is also used to send emails using OpenPGP (Open Pretty Good Privacy) and S/MIME (Secure/Multipurpose Internet Mail Extensions), user authentication using smart cards, and client system authentication using signatures or SSL (Secure Socket Layer) encryption.

You may also encounter a PKI option when accessing electronic documents and online forms that require user signatures. Although there are other ways to validate an electronic document, PKI is by far the easiest to use since the two parties do not need to know each other.

Chain of trust

To improve the security of a public key infrastructure, a trust relationship called a chain of trust is required. This hierarchy describes the trust relationships between identities when using subordinate (intermediate) certificate authorities. The main advantage of this approach is that it allows certificates to be delegated to subordinate CAs.

A chain of trust is created by verifying every hardware and software component from one end all the way to the root certificate. This is necessary to ensure that only trusted software and hardware are used in the PKI.

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