How PKI strengthens Zero Trust network security

How PKI serves as the foundation of Zero Trust architecture

Cybersecurity is critical for organizations and enterprises. However, enforcing access control and protecting sensitive data have become more challenging due to rapidly expanding infrastructures and increasingly sophisticated attack techniques. More organizations now implement Zero Trust strategies and complement them with public key infrastructure (PKI) to support user and device authentication and secure communications.

Here's what you need to know about these principles, how Zero Trust and PKI work together to enhance cybersecurity, and how to use them to strengthen your organization's security posture.

PKI vs. Zero Trust

PKI is a framework that uses digital keys and certificates (e.g., SSL/TLS and code signing certificates) for identity management and secure data exchange over networks like the internet. It leverages asymmetric cryptography, where each participant has a widely distributed public key for encrypting information and a secretly kept private key for decrypting it. Digital certificates bind public keys to specific individuals or entities to authenticate their identities.

Zero Trust Network Architecture (ZTNA) uses multiple layers of access control and continuous verification before giving users and devices access to data and applications. It’s based on the premise of “never trust, always verify.” Organizations allow access and rights made based on ongoing identity validation, device health, and other contextual factors. Principles of a Zero Trust approach include identity verification, least privilege, continuous monitoring, and micro-segmentation.

PKI and Zero Trust have different focuses: PKI establishes a secure communication framework to maintain trust in digital communications through encryption and identity verification. Meanwhile, Zero Trust emphasizes an access management model based on continuous verification to support context-aware decision-making. However, both enhance overall cybersecurity with robust measures, such as authentication processes, to ensure data confidentiality and protect against unauthorized access, data tampering, data breaches, and other security threats.

PKI is a crucial component of a Zero Trust architecture, with 96% of IT security executives saying it's essential for building a ZTNA. It enables reliable user and device authentication through digital certificates to mitigate risks associated with weak passwords and compromised credentials. Also, PKI supports secure communications through encryption to prevent unauthorized access to sensitive information, providing a practical way to implement the Zero Trust requirement of encrypting data in transit.

How PKI and Zero Trust work together to strengthen cybersecurity

PKI serves as the foundation of a resilient Zero Trust model. In particular, this certification-based access control supports passwordless solutions that overcome the weaknesses of many multi-factor authentication (MFA) schemes, such as:

• MFA tokens are susceptible to phishing and social engineering. Attackers may trick users into providing their credentials and the MFA token.
• If a threat actor gains control of a user device physically or remotely, that actor may be able to intercept MFA tokens. A ZTNA, supported by PKI, can continuously assess the trustworthiness of devices to mitigate this risk.
• Hackers may spoof or replicate biometric data used for MFA to gain unauthorized access. PKI and Zero Trust enable a layered security approach, using contextual factors to support access decisions.

Here's how organizations can combine PKI and Zero Trust to strengthen security:

User authentication

Authentication mechanisms make sure that only legitimate users can access an organization's systems, applications, or data to prevent unauthorized access to sensitive information. They help prevent data breaches, financial loss, and reputational damage.

Private PKI issues users unique digital certificates, enabling users to use a private key to access protected resources and mitigate the risks associated with compromised credentials.

Device authentication

With this process, only trusted and authorized devices gain access to an organization's resources. Device authentication protects an infrastructure from compromised endpoints in a complex environment where numerous devices access enterprise networks from multiple locations (e.g., Internet of Things devices).

ZTNA authenticates devices through dynamic access control, while PKI enhances these measures by ensuring secure identity verification through digital certificate management and continuously monitoring the certificates' validity.

Secure communications

Secure digital communications are critical for protecting sensitive data. They establish information integrity to maintain trust in digital interactions and mitigate risk of data breach.

Zero Trust assumes anyone receiving a message, even within an internal network, is potentially untrusted until verified. PKI uses asymmetric cryptography, where each entity has a unique public-private key pair, to ensure that only trusted and designated entities can decipher an encrypted message.

Data integrity

Data integrity means information shared among entities remains accurate, unaltered, and trustworthy throughout its lifecycle. Ensuring the integrity of data safeguards against financial loss, reputational damage, or misinformation

Encryption, enabled by PKI, ascertains the integrity of data by protecting it from unauthorized modification during transmission. Meanwhile, ZTNA's continuous monitoring and dynamic access control capabilities can detect compromised users or devices and promptly revoke access to sensitive data.

Implementing a Zero Trust model with PKI

Here are the critical considerations when implementing PKI to support ZTNA:

• Balance security with usability: Implement user-friendly authentication and access control workflows to minimize friction and ensure security measures don't hinder user adoption and productivity. Use single sign-on (SSO) solutions and passwordless authentication to enhance user experience without compromising security.

• Use a trusted certificate authority (CA): Your choice of CA is crucial for the trustworthiness of your PKI. Consider a CA's reputation, compliance with industry standards, and the certificate types it offers to inform your decision.
• Customize solutions for your specific requirements: Tailor your ZTNA and PKI solutions to address your security and compliance requirements and operational environments. Conduct a risk assessment, customize policies and controls to mitigate risks, and align the implementation with your workflows.
• Manage complexity: As your organization grows, scalability challenges will arise. Implement automation and orchestration solutions to streamline certificate lifecycle management. They help you manage the growing number of devices and users to increase efficiency and eliminate outages and disruptions caused by expired certificates.

Zero Trust security and automation

Automation is critical for Zero Trust security and helps manage the scale and complexity of a growing infrastructure. This way, tasks like access provisioning, monitoring, and policy enforcement stay consistent and efficient. Automation also enables real-time response to changes in user behavior, device health, and security postures in a dynamic environment.

An automation solution enables rapid threat detection and immediate incident response. For example, it can isolate compromised devices and revoke access without human delays. It also helps maintain consistency in implementing and enforcing security policies to ensure uniform application of access controls, encryption settings, and other security measures to reduce compliance violations.

Moreover, automation supports Zero Trust implementation with continuous monitoring, adaptive access control, and real-time threat intelligence integration. It's essential for scaling certificate lifecycle management to maximize the benefits of your PKI. This reduces administrative burden, prevents security vulnerabilities, and eliminates outages, disruptions, and breaches caused by expired certificates.

Building a secure enterprise with Zero Trust and PKI

PKI provides the most secure option to validate each user's or device's identity, supporting robust access control in a Zero Trust environment. Automating certificate lifecycle management allows you to scale your infrastructure, security strategy, and policy enforcement cost-efficiently while avoiding human errors or oversights that can lead to breaches and service outages.

Sectigo Certificate Manager (SCM) is a CA-agnostic platform for automating the lifecycle management of all your public and private certificates. Learn more and start a free trial to see how it can help you manage your digital certificates in one place—and support a ZTNA at the same time.

Want to learn more? Get in touch to book a demo of Sectigo Certificate Manager!

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