The Basics of PKI: How Public Key Infrastructure Works

As we experience greater technological advancements, especially with the rise of cyber threats and the growing dependence on online services, secure communication is essential. Though malicious actors are searching for much better and more catastrophic methods to exploit such technologies, it becomes increasingly important for us to employ new and improved measures to ensure the security of our infrastructure.

That said, PKI is vital in ensuring the confidentiality, integrity, and authentication of data.  It can be used in nearly every interconnected application and service deployed on the internet, making it an essential component in facilitating day-to-day operations. 

In this article, we’re going on a comprehensive study of public key infrastructure, the basics, and the nuts and bolts that make it work.

What is Public Key Infrastructure?

PKI (Public Key Infrastructure) is a system that offers resources and services required to safely handle digital keys and certificates. It builds confidence and trust between parties through confirming identities, encrypting data, and guaranteeing data integrity during transactions. 

Two key concepts of cryptography are public key and private key. The public key is shared openly to encrypt information and validate signatures. The private key is held secret by the owner and is used to generate digital signatures or decode data.  This technology ensures that data is encrypted and the sender’s identity is verified, allowing partners to work together even in untrusted networks.

PKI is built into virtually every application that requires remote communication between devices. Web browsers, VPNs, IoT devices, etc, all have built-in PKI.

Components of Public Key Infrastructure

The following are essential components of public key infrastructure:

1. Encryption

Encryption refers to converting plain text into an unreadable format to prevent unauthorized access. It helps to maintain the integrity and authenticity of data. 

There are two types of encryptions: Symmetric and Asymmetric encryption. 

Symmetric encryption is an encryption technique that uses the same key to encrypt and decrypt data. It is one of the oldest forms of encryption. 

Asymmetric encryption utilizes two separate keys, i.e., Private and Public keys, to encrypt and decrypt data. It is a modern encryption technique and is way more secure than symmetric encryption. 

2. Key

The key here refers to a long string of numbers used to encrypt data. 

There are two main types of keys: public and private keys. 

A public key is an encryption key that is available to the general public and is used for encryption and verification, while a private key is a secret key that is used for decryption and signing. 

3. Certificates

Certificates are digital documents that verify the identity and authenticity of users attempting to decrypt encrypted data. They are equipped with a public key, identity information, and a digital signature that helps devices verify users’ identity.

How does PKI Work?

Public Key Infrastructure utilizes key components like certificates and keys to secure data transmission. It utilizes asymmetric encryption to encrypt data, i.e., the public key is issued by a trusted certificate authority and made available to the public. This public key verifies the identity of the sender of the encrypted message.

A private key is then issued by the certificate authority and is used by the receiver of the message to decrypt the contents of the message.

The encryption and decryption processes are facilitated by a series of complex algorithms and mathematical equations. These complex algorithms are used to encrypt and decrypt data to ensure that when encrypted data is transmitted, it can only be accessed by the intended recipient.

What are PKI Certificates? 

PKI certificates are digital documents that facilitate the exchange of PKI keys. Here are some components of PKI certificates:

• Certificate Authority (CA): A certificate authority is the source that issues the certificates to all parties involved in a PKI key exchange. 
• Registration Authority (RA): It authorizes the creation of a certificate and provides validated user information to the CA. 
• Certificate Database: This refers to a designated unit used for storing certificates. The database is hosted on a server that stores the certificate authority. 

Applications of Public Key Infrastructure

Public infrastructures are the framework and protocols that facilitate secure connection over the internet. It is used in virtually all forms of Internet activities that require secure communication. 

The following are some of the most common applications of public key infrastructure:

1. Authentication

Popular authentication methods like 2FA are facilitated by public key infrastructure. PKI verifies users’ identities through certificates, thereby improving the security and integrity of password-protected applications. 

2. Email Security

Mailing protocols utilize PKI to assign digital certificates to the communication during the mail exchanges. 

3. Website Security 

PKIs are one of the most widely used protocols in securing web applications. Protocols like HTTPS function with the help of PKI services to ensure maximum security of websites and applications. 

4. VPNs

Virtual Private Networks (VPN) connect users to remote servers in several locations worldwide. These servers all have digital certificates that ensure the connection between the server and the user is secure. 

Conclusion

Public key infrastructure is the bedrock of modern cybersecurity, enabling secure communication, data integrity, and verification. It is an indispensable component in today’s digital infrastructure. 

PKI creates confidence in the digital environment through managing digital certificates and keys. Additionally, it guarantees that sensitive data is shielded from unauthorized access. Although the PKI application might seem challenging, its advantages outweigh the disadvantages and make it a vital tool for individuals and businesses looking to secure sensitive data. 

Understanding the basics of this technology empowers you with the knowledge needed to implement and manage digital certificates in your network or organization’s network infrastructure.