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Securing the Unified Namespace Architecture for IIoT

by Kudzai Manditereza
13 min read

In our previous article, Data and Functional Modeling for Unified Namespace, we discussed data and functional modeling for Unified Namespace (UNS). In this article, we will discuss security challenges associated with UNS in IIoT environments and offer actionable strategies and best practices to address these challenges effectively.

The concept of a Unified Namespace (UNS) has emerged as a pivotal architecture for enabling seamless integration and communication across various devices and systems in manufacturing. A UNS acts as a centralized framework, harmonizing data and processes in industrial environments, thereby driving efficiency, scalability, and innovation. However, with this integration comes a significant challenge: ensuring the security of the UNS architecture.

Integrating diverse systems within the UNS architecture inherently increases its exposure to various security threats. These threats pose risks to data integrity and privacy and can lead to operational disruptions and substantial financial losses. In an era where cyberattacks are becoming more sophisticated and frequent, particularly targeting critical infrastructure, the need for robust security measures within UNS environments has never been more urgent.

Let’s delve into the security challenges associated with UNS and examine strategies and best practices to address them effectively. From fundamental aspects like authentication and authorization to advanced considerations such as encryption, client management, and data governance, we will explore the various facets of securing a UNS.

Strategies and Best Practices for Security in UNS

Authentication and Authorization

To secure MQTT communications in your UNS, authorization for each client is crucial to prevent unrestricted access to all topics. The MQTT 3.1.1 specification acknowledges the need for authorization in hostile environments. Topic permissions set by the broker dictate what clients can publish or subscribe to, including topic specificity, operation type (publish, subscribe, or both), and quality of service level. If unauthorized, a client's attempt to publish can lead to disconnection or non-delivery of the message without notification. For subscriptions, the broker can deny access and notify the client if they lack permission for a specific topic.

  • Username and password: The MQTT protocol provides username and password fields for authenticating message exchange. The client can send a username and password when it connects to an MQTT broker.

  • Role-Based Access Control (RBAC): This involves assigning permissions based on roles within the organization, ensuring that only authorized users have access to specific MQTT topics.

  • Access Control Lists (ACLs): ACLs provide a more granular level of control, specifying which clients can publish or subscribe to certain topics.

  • Integration of OAuth2: Although challenging, using OAuth2 for MQTT broker authentication centralizes the management of access, allowing for more streamlined and secure control of user permissions.

Encryption and Secure Communication

MQTT operates over TCP, which by default, is unencrypted. Many MQTT brokers, including HiveMQ, support TLS as a substitute for plain TCP for secure UNS communication. This is especially important when using MQTT CONNECT packet's username and password for authentication and authorization, to ensure data security. Port 8883 is the standardized, reserved port for MQTT over TLS, known as “secure-mqtt”, ensuring exclusive and secure MQTT communications.

  • Transport Layer Security (TLS/SSL): This protocol encrypts data in transit, protecting it from interception and tampering.

  • Secure WebSockets and VPNs: For environments where TLS might not be suitable, using secure WebSockets or operating within a Virtual Private Network (VPN) can offer additional security layers.

  • Certificate Management: Ensuring proper management and regular updates of certificates used in TLS/SSL is crucial for maintaining encryption integrity.

Client Identifier (ClientID) Management

The structure and validation of ClientIDs are critical for defining access rights. A well-designed ClientID can be integrated into the topical structure, ensuring that clients only access permitted topics.

  • Dynamic Integration of ClientID in Topic Structure: This strategy allows for the dynamic allocation of rights based on the ClientID, providing a secure way to manage access at the topic level.

  • Validation and Persistence of ClientIDs: Ensuring that ClientIDs can be validated and are consistent across sessions enhances security. This also facilitates the use of persistent sessions, beneficial in unstable network conditions.

  • Meta-Information Utilization: Using meta-information from ClientIDs for authorization purposes adds an additional layer of security by ensuring that only clients belonging to certain groups can access specific topics.

Securing Your MQTT Infrastructure for UNS

Securing MQTT infrastructure involves understanding network topology and implementing measures to prevent unauthorized access and system downtimes. Key strategies include:

  • Firewall: Use firewalls to filter traffic, blocking unexpected or unnecessary traffic like UDP and ICMP packets, while allowing MQTT traffic on standard ports (1883 for TCP, 8883 for TLS).

  • Load Balancer: Employ load balancers to distribute MQTT traffic across multiple brokers, preventing overloading and enabling traffic throttling in high-traffic scenarios.

  • DMZ (Demilitarized Zone): Set up a DMZ for internet-facing services like MQTT brokers, with additional firewall protection to secure access to internal systems and services.

High Availability and Redundancy 

Setting up MQTT broker clusters in each plant and a central cluster in the cloud can mitigate the risk of single points of failure. This approach ensures that even if one broker is compromised, others can take over, maintaining network integrity.

  • MQTT Broker Clusters: Implementing MQTT broker clusters in each plant and a central cluster in the cloud enhances resilience. In this setup, if one broker fails or is compromised, others in the cluster can continue to operate, minimizing downtime and potential data loss.

  • Geographical Distribution: Distributing these clusters across multiple availability zones can further reduce risks related to regional outages or disasters.

  • Failover Mechanisms: Implementing automated failover mechanisms ensures a seamless transition between brokers in case of failure.

Data Governance and Training 

This approach ensures that everyone understands the system's structure and the importance of security, reducing the risk of inadvertent breaches.

  • Comprehensive Data Governance: This involves the entire architecture, ensuring all users know and comply with data security policies.

  • Reskilling and Training: Regular training programs for staff to understand the security implications and proper use of MQTT systems are vital. This helps in building a culture of security awareness across the organization.

  • Decentralized Data Governance: Encouraging a decentralized approach, where every employee acts as a data steward, can enhance security by distributing responsibility.

Regular Updates and Monitoring

Keeping MQTT brokers and clients in your UNS updated and employing monitoring tools for anomaly detection is vital for maintaining a secure environment.

  • Automated Patch Management: Keeping MQTT brokers and clients updated with the latest security patches is crucial. Automating this process ensures the timely application of updates.

  • Anomaly Detection: Implementing advanced monitoring tools that can detect unusual network activity or access patterns helps in the early identification of potential security breaches.


In conclusion, the security of a Unified Namespace (UNS) is a multifaceted endeavor requiring a comprehensive and proactive approach. As detailed in this article, employing strategies such as robust authentication and authorization, encryption and secure communication, and diligent ClientID management are foundational to securing UNS environments. Equally important are the infrastructural aspects, including effective firewall implementation, load balancing, and the establishment of demilitarized zones (DMZs).

High availability and redundancy through MQTT broker clusters and geographical distribution ensure continuity and resilience in the face of potential breaches or system failures. Additionally, a strong emphasis on data governance and continuous staff training creates a culture of security awareness and readiness, which is crucial in mitigating risks associated with human error.

Ultimately, the security of UNS is not a one-time task but an ongoing process of adaptation and improvement. As technology evolves and new threats emerge, organizations must remain vigilant and responsive, continuously refining their security strategies to safeguard their operations and data effectively.

Unlock the power of Unified Namespace (UNS) architecture. Download our comprehensive eBook titled 'Architecting a Unified Namespace for IIoT with MQTT' to discover strategies and best approaches to effective UNS implementation and take your industrial systems to the next level.

Kudzai Manditereza

Kudzai is a tech influencer and electronic engineer based in Germany. As a Developer Advocate at HiveMQ, he helps developers and architects adopt MQTT and HiveMQ for their IIoT projects. Kudzai runs a popular YouTube channel focused on IIoT and Smart Manufacturing technologies and he has been recognized as one of the Top 100 global influencers talking about Industry 4.0 online.

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