Compare and Buy Device Certificates

What is Mutual TLS? mTLS Guide

Mutual TLS, often referred to as mTLS, is a type of mutual authentication. mTLS improves an organization’s security posture by confirming the authenticity and validity of both the client and the server, making it one of the most trusted forms of authentication. With mTLS, the main goal is to ensure that both parties, the client (i.e., browser) and the server, are who they say they are by verifying that they both have the correct private key for decryption. This two-way form of authentication also takes into account their TLS certificates – which provide additional verification details – before they are marked as trusted.  

Before we dive deeper into the ins and outs of mTLS, let’s cover the basics of TLS (the underlying protocol for establishing secure communications).

mTLs 101: What is TLS?

Transport Security Layer, which you’ll see referred to as TLS, is one of the most widely used encryption protocols on the internet. You can tell a website is using TLS when the URL begins with https://.

TLS authenticates the server in a client-server connection and encrypts any communication between that client and server. TLS uses public key cryptography, using two keys: a public key and a private key. If something is encrypted with the public key, only the private key can decrypt it. So, when a server decrypts a message with the public key, it confirms that it has the matching private key.

Usually, the TLS authentication process looks like this:

1. The client connects to the server
2. The server shows the TLS certificate os its digital ID
3. The client validates the server’s digital certificate
4. Once authenticated, the client and server exchange encrypted data over the TLS connection

TLS vs. mTLS: Mutual TLS Authentication Explained

In mTLS, both the client and server have digital certificates, and they use these certificates to prove their trustworthiness to each other through their public/private key pairs. Before they start communication, they need to show their digital certificates to confirm their legitimacy. Since mTLS demands this two-way or mutual TLS authentication, it’s seen as a more secure method, though it takes a few extra steps for authentication.

1. The client connects to the server
2. The server shows the TLS certificate as its digital ID (for example, amazon.com)
3. The client validates the server’s digital certificate
4. The client shows its TLS certificate to prove its digital ID (for example, john.doe@gmail.com)
5. The server validates the client’s TLS certificate
6. The server grants the client access
7. After mutual TLS authentication, the client and server communicate over the encrypted TLS connection

When Do You Use Mutual TLS?

Mutual TLS authentication is TLS’s more secure cousin. mTLS builds on TLS’s authentication principles – like key pairs and digital certificates. But it takes security up a notch with two-way authentication, making it the ideal choice to secure an organization’s high-risk endpoints, such as its network and applications. While one-way authentication (TLS) does the job for most online situations, mutual TLS is more secure because it ensures only authorized users can access the system.

Zero Trust in Securing Devices

Zero trust is a security framework that mandates the authentication, approval, and ongoing validation of all users and devices before they can access the network, data, or applications. A fundamental principle of this framework is to assume that an attacker is already inside the network and, therefore, secure all other endpoints to prevent unauthorized access to additional data. Mutual TLS authentication is a key enabler of the zero trust framework as it adds an extra layer of authentication, ensuring that the user/device is who they claim to be and validating their access.

As IoT devices continue to become more and more ingrained in our lives, allowing us to remotely control home lighting, adjust thermostats with our smartphones, and monitor health metrics such as glucose levels, their widespread adoption has also brought along some tricky challenges for the cybersecurity industry.  For organizations, one major security worry with IoT devices is unauthorized access. Without the proper device certificates, hackers can exploit vulnerabilities in IoT devices to gain access to confidential information. Then, with this information, they’re sometimes able to attack other devices within the network – or even the network itself.

While IoT devices pose unique threats to organizations at a global level, there’s a solution: device certificates.

What are Device Certificates

A device certificate, also known as a client certificate, is the digital certificate essential for enabling mTLS or mutual authentication. The device certificate plays an important role in securing the connection between a client and a server, acting as a digital ID for the device. Through mutual TLS authentication, these digital certificates enable devices to connect with an organization’s internal network, applications, or even other devices.

Typically, organizations issue these certificates through their private certificate authorities (CAs). Nonetheless, managing billions of device certificates, particularly for IoT manufacturers, can pose a challenge, particularly when dealing with everything that device certificate management entails.

If you’re keeping track of device certificates, you’ll need to consider:

• The issuance process for device certificates
• The employees responsible for managing digital certificate lifecycles
• The devices on your networks and IT environments
• Which devices (if not all) are secured with device certificates
• When device certificates expire

Conclusion

To wrap up, mTLS is like TLS’s more security-minded cousin. Mutual TLS authentication uses two-way authentication to add an extra security and identity verification layer, verifying that both parties are legitimate. While TLS certificates offer secure authentication and can be useful for securing client-server communication on the internet, they’re not built for the high-stakes security environments of an organization’s internal network or IoT device manufacturing. Those requiring a more secure solution should consider device certificates, which rely on mutual TLS authentication.