Digital protection for IoT/OT devices

The Internet of Things (IoT) and Operational Technologies (OT) are becoming increasingly important to modern industrial processes. According to, there will be 15 billion IoT devices in use by 2023. This number is expected to almost double to around 29.5 billion by 2030.

However, increasing integration also poses security challenges. Cyber-attacks are becoming more sophisticated and complex. The protection of digital infrastructures and networked devices is therefore becoming a key challenge.

What is the role of Public Key Infrastructure (PKI) in the digital protection of IoT and OT devices? How does it help ensure the security of identities of all kinds?

The two concepts are fundamentally different. But they are converging, creating synergies between connected devices and industrial automation (Industry 4.0).


Differences between IoT and OT

The growing importance of security in connected environments

Why is security crucial in the IoT/OT environment?

The Public Key Infrastructure (PKI)

Securing the IoT – Scalable Security Solutions with PKI (IoT PKI Solutions)

How PKI enables scalable security (PKI enables IoT Security)

Device Identity and Certificate Lifecycle Management

Smart Cities: Integrating IoT devices with PKI

How essendi xc optimally monitors the lifecycle of certificates

Managed PKI as an effective IoT solution

How an MPKI creates trust between devices and systems


Differences between IoT and OT


Field of application Connected devices in various sectors such as smart homes, healthcare, transport, agriculture, industry, manufacturing… Specific to industrial and commercial environments; focus on process control and automation (transport to production)
Communications/Protocols Wireless technologies (Bluetooth, WLAN, …) and standardised IoT protocols (MQTT, COAP, …) Specialised communication protocols for reliable real-time control (e.g. OPCUA, Modbus protocol,…)
Data management Collecting, analysing and using data to generate new insights and added value Real-time process control, data used to optimise processes
Protection of personal data
Prevent unauthorised access to networked devices
Unique identification of own devices (zero trust)
Secure, encrypted data traffic
Guarantee integrity
Ensure availability and reliability of industrial processes
Unique identification of own devices
Flexibility/Scalability Flexible and easily scalable, designed for a wide range of applications and environments Tailored to specific industrial requirements and defined environments Must be robust and reliable
Storage capacity from limited to common/expandable extremely limited
Examples of devices Smart home devices
Wearables (smartwatches, …)
Infotainment systems in cars
GPS-guided agricultural machinery
Intelligent parking systems
Connected machines in production
IP cameras
Building management systems
Asset monitoring with maintenance scheduling
Medical equipment (X-ray machines, MRI)
Industrial control systems (PLC, RTU, DCS)
Process control systems (DCS)
Measurement and control devices (sensors, pressure, temperature, …)
Traffic control systems
Manufacturing systems (robotic systems, CNC machines)
Pumps and valves


Growing importance of security in connected environments

IoT and OT devices (connected devices/networked devices) are becoming increasingly connected. This leads to increased security requirements in business-critical processes. Sensitive data, such as personal information and industrial control data, must be protected from unauthorised access.

In many areas of an organisation, IoT and OT systems are an integral part of critical infrastructure. Disruptions in KRITIS enterprises (e.g. power and water supply) can have a serious impact on society as a whole.

Secure machine identities are particularly important in these areas. They are the basis for ensuring that sensors or measurement and control devices can exchange their data securely.

In addition to the actual data access, the unambiguous determination of identities is now part of the list of requirements for IoT/OT. It must be ensured that only the user’s own devices are in use. Third parties must not be able to smuggle unauthorised devices into the network for the purpose of spying or manipulation.

This has led to more stringent regulatory requirements. Companies and organisations must comply with increasingly stringent security standards to avoid legal consequences.

Another difficulty in this environment is the maintainability of devices. They are often responsible for operational safety and organisations are dependent on the correct performance of equipment activities. As a result, there are increased demands on the maintenance and upkeep of equipment.


man with glassesWhy is security crucial in the IoT/OT environment?

There are many risks and threats in the IoT/OT environment. Data breaches can have serious consequences in both IoT and OT systems. Physical threats from attacks on connected devices, as well as cyber-attacks and malware, pose additional challenges. Lack of authentication, access control and security updates increase vulnerability, while lack of standardisation and human error pose additional security risks.
Robust security measures are essential to counter these threats. Key examples include encryption, authentication, regular software updates and user training.


top view of a city with different streets by nightThe Public Key Infrastructure (PKI)

PKI is a system that enables the creation, management and use of digital certificates. This ensures secure data transmission and authentication on networks. Digital certificates provide security by enabling secure communication, identity management and protection against cyber-attacks.

In the PKI for IoT devices, certificates are used for authentication and access control. They enable the secure verification of the identity of users, devices (device identities) or services. They are also incorporated into access control mechanisms. Certificates enable encrypted communication, protect data from tampering and theft, and prevent man-in-the-middle attacks.

Digital signatures in IoT and OT ensure the integrity of data and the authenticity of messages. They contribute to the security and integrity of communication and control in networked environments. Certificates establish trust in digital interactions (trust anchors) through the signature of trusted Certificate Authorities (CAs). They ensure the authenticity of digital identities.

Read more about PKI in our magazine.


Securing the IoT – Scalable Security Solutions with PKI (IoT PKI Solutions)

A particular challenge is the scalability of the IoT security solution in networked environments. It must be able to adapt to different requirements:

  • The large number of communicating devices poses a management and security challenge.
  • Different types of devices from different manufacturers make it difficult to implement standardised security measures.
  • The dynamic nature of networked environments, where devices are constantly being added or removed, requires flexible scalability.
  • The need to process large amounts of data in real time requires a scalable infrastructure. It must be able to cope with high transmission speeds without compromising security.

The following questions can help you assess the requirements for a PKI in your own organisation:

  • What devices do you need to secure?
  • What use cases do you need to cover?
  • How many locations in the organisation require PKI services?
  • How scalable and flexible does the PKI need to be?


How PKI enables scalable security (PKI enables IoT security)

Public Key Infrastructure provides a trusted foundation for managing digital identities through protocols and mechanisms. It ensures reliable communication through

  • Efficient key management
    Optimising the process of key generation, distribution and rotation to maintain security in a scalable environment.
  • Certificate Authentication
    Provides scalable authentication of devices and users. Digital certificates are used as a unique proof of identity. Used as an additional layer of protection in conjunction with key attestation.
  • Building trust
    The hierarchical structure of the PKI, especially with trusted CAs, helps build trust.
  • Encryption and integrity protection
    Digital signatures provide data encryption and integrity protection. This is particularly important in networked environments with large amounts of data.


Device Identity and Certificate Lifecycle Management

A trusted device identity is the foundation for secure authentication, privacy and access control in a complex network. Each device must have a unique identifier and security certificates. This is the only way to ensure unique authentication.

The certificates play a key role in access control and guarantee the integrity of all communications. Depending on the characteristics of the certificates, they can contain unique device identities. These are verified using key attestation, similar to fingerprints on an ID card.

Certificate lifecycle management is also critical to reliable security. This includes their application, retrieval, installation and use, as well as regular renewal. In the event of compromise, lifecycle management includes the rapid revocation of certificates.

The entire process is optimised through automation using a certificate management tool such as essendi xc. This is particularly important in the IoT/OT environment where many certificates are used and need to be managed.

Smart Cities: Integrating IoT devices using PKI

important role in areas that benefit from improved efficiency, sustainability and quality of life through the use of IoT technologies and intelligent systems.

These include urban planning, public administration, environmental management and transport. In these areas, they help to optimise services, increase energy efficiency and improve quality of life.

In the healthcare sector, smart city technologies enable improved healthcare services and real-time monitoring of patient data.

Civil engineers and architects are integrating smart technologies into buildings and infrastructure to promote sustainability and efficiency.

IT and telecommunications experts provide the necessary infrastructure for connectivity and security.

This multidisciplinary collaboration is driving the development of smart cities. It makes them safer, more sustainable and improves urban life.

A PKI is essential for smart cities. It ensures the security and trustworthiness of connected IoT devices. It is therefore the backbone of cybersecurity in smart cities.

For example, PKI systems support secure remote maintenance and control of devices. They also enable scalable and efficient management of device identities. This is important in the complex and dynamic environment of a smart city.


xc - the customisable certificate management tool

Certificate Automation

Automating certificate management minimises the need for manual intervention. This reduces the risk of human error, which can lead to security breaches. Certificates are renewed, monitored and updated in a timely manner without the need for human intervention (enabling secure management).


Seamless monitoring keeps you in control of all certificate processes in the organisation. For example, essendi xc prevents downtime caused by invalid certificates.
This can happen when defective devices are taken out of service but the certificate is not revoked. At the same time, any resulting security gaps are closed.


The certificate request forms in essendi xc make corporate compliance very easy. The tool adheres to compliance requirements according to customer-specific specifications. User groups can request their certificates from specific CAs according to defined authorisations.

In addition, xc creates a concept for the use of keys, documents their lifecycle and the procedures used.

Together, device identity and controlled lifecycle management form the basis for the security of IoT/OT devices.


Managed PKI as an effective IoT solution

A Managed PKI (PKI as a Service) is provided by a specialised service provider.

An MPKI is an ideal solution for organisations with a large number of IoT/OT devices. It enables efficient and secure management of large numbers of digital certificates.

The MPKI provider’s expertise in cryptography and security, as well as the implementation of proven standards, ensures a reliable infrastructure.

The scalability and flexibility of MPKI enables organisations to quickly adapt to changing requirements. As a result, they can operate their networked environments securely at all times.

Read more about Managed PKI in our magazine.


How an MPKI establishes trust between devices and systems

Both PKI and MPKI use hierarchical structures. Trusted CAs and their signature processes play a central role as trust anchors. This makes it possible to prove that the digital identity has been verified by a credible authority. Proof can be provided either procedurally or by uniquely identifying the device’s UID (key attestation).

Certificate management tools can significantly increase security through extensive automation. Security standards are consistently applied and human error is eliminated. This strengthens the integrity and authenticity of networked devices.

Want to learn more about the benefits of certificate management tools? We would be happy to show you the strengths of essendi xc in a live demo. Simple and without obligation. If you wish, we can also address your specific use cases.