What Is a Certificate Authority?

How can you be sure the logged-in users really are who they say they are? What about the websites you access, or the apps you use?

Modern organizations need a way to reliably verify the identities of users, devices, servers, and applications before granting access. Passwords, while a good start, are difficult to manage at scale, especially when teams need secure access to networks and other internal infrastructure.

That’s where a Certificate Authority (CA) comes in to help verify the legitimacy of an identity.

So, how does a Certificate Authority work, and why does it matter for secure access control? Let’s explore.

What Is a Certificate Authority?

A Certificate Authority is a trusted entity that issues and signs digital certificates that help prove a website, user, device, server, or application is who or what it’s stated to be. The Certificate Authority not only creates certificates but also validates identities, signs certificates, and helps determine whether an identity can be trusted.

For instance, when you connect to a website, its identity is authenticated through an SSL/TLS certificate. This confirms that the website is what it’s stated to be and enables secure, encrypted connections. In these cases, that trust relies on the CA behind the SSL/TLS certificate.

Why Certificate Authorities Matter

So, why does this matter? Maintaining trust and authenticating identity is essential for cybersecurity, and Certificate Authorities support secure digital identity and authentication to provide that trust. This works in many ways, including:

• Verifying the identity of websites, users, devices, servers, and applications.

• Enabling encrypted communication through SSL/TLS certificates.

• Supporting certificate-based authentication for network access.

• Reducing reliance on shared credentials.

• Helping organizations manage trust at scale.

• Supporting stronger access control and audit readiness.

In short, a Certificate Authority is a core aspect of establishing and maintaining digital trust. Without it, online work and communication would be significantly riskier and less reliable.

How Does a Certificate Authority Work?

Knowing how CAs work helps us understand what makes it a reliable source of identity authentication as well as what it can and can’t do. Certificate Authorities work like so:

• A certificate request is created: First, a user, device, server, or application enrolls for a certificate, often through a certificate signing request or automated enrollment process. The certificate can then be used later during authentication.

• The Certificate Authority validates the request: Before the certificate is issued, the Certificate Authority checks to verify that the request can be trusted, then validates the request.

• The CA issues and signs the certificate: Once the request has been validated, the Certificate Authority uses its private key to digitally sign the certificate.

• The certificate is presented during authentication: The certificate is then shown to a browser, network, VPN, server, or authentication system (depending on what’s being verified and how they’re connecting).

• The receiving system checks whether the certificate is trusted: Next, the receiving system checks whether the certificate chains back to a trusted Certificate Authority, has a valid signature, has not expired, has not been revoked, and meets the required policy conditions. If those checks pass, the system can trust the identity for that authentication request.

• The certificate is renewed, replaced, or revoked when needed: Certificates don’t last indefinitely. They have lifecycles and must be managed over time, so renewing, replacing, and revoking them is part of the process.

How Certificate Authorities Fit Into PKI

Now let’s talk about Public Key Infrastructure (PKI). This is the broader system of technologies, keys, certificates, and policies that make certificate-based trust work, so knowing what it is and how it works provides the foundation for understanding Certificate Authority.

PKI includes the following:

Root Certificate Authority

Root Certificate Authority is the highest trust anchor in the certificate hierarchy. This is what other certificates trace their trust back to, essentially making it the final say in trust and authentication. As such, it’s highly sensitive.

Intermediate Certificate Authority

Between the root Certificate Authority and the certificates used daily is the intermediate Certificate Authority. These help limit direct use of the root Certificate Authority, maintaining its security while still providing authentication and verifying trust.

Issuing Certificate Authority

The issuing CA handles certificate issuance for users, devices, servers, and applications. It verifies identities and issues digital certificates that support authentication, secure communication, or signing, depending on the use case.

What Are Digital Certificates Used For?

So, what exactly are the digital certificates used for? As established, they validate trust and identity, but that can serve many different use cases. This includes:

• Website security: Websites use SSL/TLS certificates issued by Certificate Authorities to help browsers verify the site and encrypt traffic.

• Device authentication: Certificates help prove that a device is authorized, so it can access networks, files, or other sensitive information as allowed.

• Wi-Fi authentication: When users connect to a Wi-Fi network, the certificates can allow approved users and devices to connect securely to a trusted network.

• VPN authentication: VPNs can provide remote employees with access to internal networks, but that access must remain secure. Certificates can help verify access before granting a connection, ensuring that only authorized users connect to the VPN.

• Server authentication: Certificates help systems verify that servers are trusted, keeping users safe from unverified or unsafe servers.

• User authentication: Certificates can help verify user identity without relying solely on passwords, adding an additional layer of cybersecurity when users log in.

• Code signing: Certificates help verify that software is from a trusted publisher, helping avoid fake or unsafe programs.

Public Certificate Authorities vs Private Certificate Authorities

Not all Certificate Authorities serve the same purpose. There are private and public CAs, and while they’re both essential for authenticating identities and permissions, they serve very different purposes. While Public Certificate Authorities are typically associated with websites and browsers, private CAs are often used within organizations for internal authentication, helping keep users verified and maintain proper permissions.

Public Certificate Authorities

Public Certificate Authorities are typically used for public websites and internet-facing services. They issue certificates that help browsers and operating systems verify that they are connecting to the intended domain and enable encrypted communication.

Private Certificate Authorities

Private CAs, on the other hand, are used within individual organizations. These issue certificates for internal purposes, such as for systems, users, devices, applications, or VPNs, to authenticate the connections and maintain security.

Private Certificate Authorities are particularly important for certificate-based access control within an organization. With them, companies can define and manage their trust boundaries, setting strict controls over who can connect, which devices they can use, what they can access, and which applications are allowed.

How Certificate Authorities Support Network Access Control

Certificates are used for authenticating far more than just websites. They can help verify users, devices, applications, servers, networks, and more, making them essential security features.

In fact, verifying users and devices is common, as it ensures that only authorized users can access Wi-Fi, VPNs, or other internal systems. This typically uses RADIUS authentication and 802.1X network access control, enabling centralized management of user access through communication between a RADIUS server and clients.

Certificate-based control for network access provides many benefits, including:

• Each device can have its own unique certificate, providing greater authentication and security.

• Access can be tied to trusted users and managed devices, so unknown or unauthorized users can’t connect.

• Certificates reduce reliance on shared Wi-Fi passwords, improving security and preventing anyone with a stolen password from connecting.

• Lost, stolen, or retired devices can have access removed, so thieves can’t access the network.

• Onboarding and deprovisioning become easier to manage.

• IT teams can implement stronger access controls without increasing the password burden on users.

Certificate-Based Authentication vs Password-Based Authentication

So at this point, you might be wondering if certificate-based authentication is really necessary if you use passwords for everything, or what the difference between the two is.

Passwords can be difficult to secure and manage at scale, especially when teams need to verify both users and devices before granting network access. Certificate-based authentication gives IT teams another way to verify trusted identities without relying only on passwords.

We can break down the differences like so:

This doesn’t mean that certificate-based authentication makes passwords obsolete or eliminates the need for other access policies. Robust, multi-layered security is vital for providing the best possible protection. However, certificate-based authentication provides IT teams with a strong baseline and a robust trust model for managing users and devices.

Common Certificate Authority Risks and Management Challenges

Certificate Authority is a powerful tool for trust and authentication. Systems may trust certificates signed by a CA when the certificate chain, validity period, revocation status, and policy requirements check out, which means the CA must be protected and managed carefully. As a result, IT teams should be aware of several challenges when relying on CA.

Common risks and challenges include:

• Expired certificates, which can disrupt access until they’re updated.

• Poor certificate renewal processes, which make it difficult to reestablish trust.

• Weak protection of CA private keys, as compromised keys can jeopardize security.

• Misconfigured certificate policies that disrupt the certification process.

• Lack of visibility into issued certificates, making them harder to manage.

• Incomplete revocation processes, which leads to certificates remaining even when they should have been revoked.

• Former users or unmanaged devices retaining access longer than they should.

• Manual certificate workflows that create operational gaps.

Best Practices for Managing Certificate-Based Trust

It’s clear that properly managing certificate-based trust is essential for maintaining security and authenticating users. However, this also means that it must be handled carefully, so IT teams will want to keep best practices in mind when setting up and managing a Certificate Authority.

Best practices include:

• Use a clear CA hierarchy for trust management to maintain security and reduce confusion.

• Protect CA private keys with strong controls to prevent bad actors from compromising them.

• Define certificate issuance policies to make sure permissions are properly applied.

• Track certificate expiration and renewal dates to keep them up to date.

• Revoke certificates when users or devices should no longer have access.

• Avoid shared credentials, especially where certificate-based access is a better fit.

• Integrate authentication workflows with identity providers (where possible).

• Maintain logs for access visibility, accountability, and audit readiness.

How Foxpass Helps With Certificate-Based Network Authentication

When you’re looking for secure, certificate-based network authentication, you’ll want a solution that can reliably let authorized users connect while maintaining security and identity verification. That brings us to Foxpass.

Foxpass Cloud RADIUS helps organizations control who can access their Wi-Fi and VPN networks using secure user and device authentication. It supports passwordless, certificate-based authentication, allowing approved users and devices to present certificates for validation before connecting. This helps reduce reliance on shared credentials and gives IT teams stronger control over who and what can access the network.

Foxpass also integrates with leading identity providers, including Microsoft Entra ID, Okta, Google Workspace, and OneLogin. When users are added, changed, or removed in your identity provider, Foxpass helps keep access aligned so teams can simplify onboarding and deprovisioning.

As a result, Foxpass provides several benefits to support IT compliance requirements, audit readiness, and security, including:

• More secure Wi-Fi and VPN access.

• Less reliance on shared passwords.

• Easier user and device authentication.

• Simplified access management.

• Stronger control over who and what can connect to your network.

When Should You Use Certificate-Based Authentication?

If, after reading this article, you’re still unsure if certificate-based authentication is useful for your company, it’s easy to evaluate your needs and determine if it’s the best choice. Certificate-based authentication is particularly useful for organizations that want stronger control over what users and devices can access, but we can break it down further.

You should use certificate-based authentication if:

• You need to secure Wi-Fi or VPN access for employees.

• You want to reduce reliance on shared passwords and ensure only authorized users can connect.

• You need to authenticate both users and devices, rather than relying on basic account logins.

• You use managed devices and want stronger access control.

• You need faster onboarding and deprovisioning when employees join or leave.

• You want better visibility into who and what is connecting to your network to maintain visibility and accountability.

• You’re preparing for security reviews, audits, or compliance requirements and need to demonstrate strong security and authentication.

Secure Network Access Starts with Trusted Identity

Certificate Authority forms the foundation for digital trust. With it, organizations can more reliably verify identities, issue certificates, and support secure communications, and IT teams can secure their networks. Without it, unauthorized users and devices can more easily infiltrate a network or otherwise compromise accounts.

Foxpass Cloud RADIUS helps organizations strengthen Wi-Fi and VPN access control with certificate-based authentication for users and devices. IT teams can reduce reliance on shared credentials, simplify onboarding and deprovisioning, and gain stronger control over who and what can connect.

Want to see how Foxpass Cloud RADIUS can keep your networks safe? Get started with a free trial today: