Protecting Millions of Devices, Not Just Connections
As IoT expands from thousands to millions of devices, every connection becomes both valuable and vulnerable. MQTT has become the backbone of IoT communication because it is lightweight and efficient, yet true security requires much more than encryption.
In industrial environments, devices operate far from data centres; on factory floors, in substations, and across remote assets, making large-scale MQTT deployments a potential target. The question is no longer “Is MQTT secure?” but “How do you secure MQTT at scale?”
That is exactly what Cumulocity’s Managed MQTT Service was built to do.
Security Built In, Not Added Later
Cumulocity, trusted by more than 200 enterprises and managing over 20 million connected devices worldwide, embeds protection into every layer of its Managed MQTT Service. Validated for 100 million concurrent devices, the service is designed for secure, multi-tenant IoT at global scale.
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Multi-Tenancy and Device Isolation
Each tenant and device operates within its own isolated topic hierarchy. Devices cannot publish or subscribe outside their own namespace, even within the same tenant. This prevents cross-device access and stops a single compromised device from affecting others. -
Certificate-Based Authentication
Static passwords and shared keys cannot scale securely. Cumulocity uses X.509 certificates bound to each device’s MQTT client ID. A built-in private Certificate Authority simplifies lifecycle management—issuing, renewing, and revoking certificates automatically. Cumulocity also allows you to use your existing PKI system; providing full flexibility for certificate based authentication. -
End-to-End Encryption
All MQTT communication is encrypted using bi-directional TLS, ensuring confidentiality and integrity across millions of messages. Even at one million messages per second, optimized broker design keeps latency low and performance consistent.
Compliance by Design
Industrial IoT security must also meet strict regulatory and operational requirements. Cumulocity has been in the IoT SaaS space for a considerable time and complies with the following standards, which means the Cumulocity’s Managed MQTT Service is de facto also compliant with:
- GDPR for data privacy
- ISO 27001 for information security management
- SOC 2 Type II for verified controls across security, availability, and integrity
Smart Security at the Edge
The edge is where most IoT risks appear, but it is also where Cumulocity extends protection.
Using thin-edge.io, lightweight devices authenticate, encrypt, and manage MQTT traffic locally before bridging securely to the cloud. The same security model applies end to end, from device to data centre.
Simple Operations, Secure at Scale
Securing millions of devices should not create unnecessary complexity.
Cumulocity provides central policy management, automation, and low-code configuration, allowing teams to:
- Onboard devices securely in bulk
- Rotate certificates or credentials across fleets
- Monitor connections and audit compliance from a single pane of glass
With 99.5 percent SLA uptime, the service delivers the resilience required for mission-critical systems.
Security and Scalability Together
Cumulocity’s Managed MQTT Service proves that IoT security and scalability strengthen each other. By embedding protection into the architecture, the platform offers:
- Isolation without complexity
- Encryption without performance loss
- Compliance without extra configuration
Whether managing smart meters, industrial machines, or connected vehicles, organizations can scale confidently, knowing every device and message is protected.
The Bottom Line
In IoT, one vulnerable device can compromise an entire network. Cumulocity removes that risk at scale, delivering proven security for up to 100 million devices with enterprise-grade reliability.
It is MQTT engineered for the real world. Secure by default, scalable by design, and simple to operate.
Learn how Cumulocity’s Managed MQTT Service protects your IoT data from edge to cloud while enabling growth without compromise.
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