What is Public Key Infrastructure (PKI) in Cyber Security?

What is Public Key Infrastructure (PKI) in cyber security

Public Key Infrastructure (PKI) is a critical element in the world of cyber security.

It is a system that ensures secure electronic transactions through a set of policies, procedures, hardware, software and services.

The global PKI Market is experiencing significant growth, estimated to be worth USD 5.5 billion in 2023 and projected to reach USD 13.8 billion by 2028, as reported by MarketsandMarkets™.

We explore the intricate details of Public Key Infrastructure, its importance in cyber security, and how it works.

What is Public Key Infrastructure (PKI)?

Public Key Infrastructure, commonly known as PKI, is a technology for authenticating users and devices in the digital world.

It is a system of digital certificates, certificate authorities (CAs), and other registration authorities that verify and authenticate the validity of each party involved in an electronic transaction.

The components of Public Key Infrastructure

Cyber security professionals ensure secure data using Public Key Infrastructure.

Public Key Infrastructure comprises several components that work together to provide security in the digital space. These components include:

  • Digital certificates: These are electronic documents that contain the public key of a user and are used to prove the identity of the user.
  • Certificate authorities: These are trusted entities that issue and manage digital certificates.
  • Registration Authorities (RAs): These are entities that verify the identities of users before they are issued digital certificates by the CAs.
  • Private keys: These are secret keys that are used to decrypt data that has been encrypted with the corresponding public key.
  • Public keys: These are keys that are used to encrypt data. They are made public so that anyone can use them to encrypt data.

Why is PKI important in cyber security?

Organisations using Public Key Infrastructure as the backbone of security protocol.

PKI plays a pivotal role in cyber security. It is the backbone of many security protocols and provides a way for users to establish and maintain a trustworthy networking environment.

Public Key Infrastructure does this by providing services such as confidentiality, integrity, authentication, and non-repudiation.

PKI in secure communication

One of the primary uses of PKI in cyber security is in secure communication. PKI is used in protocols such as Secure Sockets Layer (SSL) and Transport Layer Security (TLS) to secure web traffic.

These protocols use Public Key Infrastructure to authenticate the server to the client and to encrypt the data being transmitted between the two.

PKI is also used in email encryption and digital signatures. It ensures that only the intended recipient can read the email and verifies that the email has not been tampered with during transmission.

Digital signatures, on the other hand, use PKI to verify the identity of the sender and to ensure that the sender cannot deny sending the email.

How does Public Key Infrastructure work?

User in sending secure messages using Public Key Infrastructure.

PKI works by using a pair of keys – a public key and a private key. The public key is made available to everyone, while the private key is kept secret by the user.

When a user wants to send a secure message, they encrypt it using the recipient’s public key. The recipient can then decrypt the message using their private key.

Steps involved in PKI

The process of using PKI involves several steps:

  • Key generation: The user generates a pair of keys – a public key and a private key.
  • Certificate request: The user sends a request to a CA for a digital certificate. The request includes the user’s public key and some identification information.
  • Certificate issuance: The CA verifies the user’s identity and issues a digital certificate that contains the user’s public key and identification information.
  • Certificate use: The user uses the digital certificate to authenticate themselves to others. Others can use the public key in the certificate to encrypt messages to the user.
  • Certificate revocation: If the user’s private key is compromised or their identification information changes, the CA can revoke the digital certificate.


Public Key Infrastructure is a crucial aspect of cyber security. It provides a framework for authenticating users and devices, ensuring the confidentiality and integrity of data, and providing non-repudiation.

As cyber threats continue to evolve, the importance of PKI in cyber security cannot be overstated.

Whether you’re an individual or a business, understanding and implementing PKI should be a key part of your cyber security strategy.

You can deepen your understanding of PKI by enrolling in the Institute of Data’s specialised Cyber Security program, designed for full-time and part-time students.

For personalised guidance in your cyber security career, schedule a complimentary consultation with our team of experts to discuss our programs and how they might be right for you.

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