Protecting the security and integrity of your industrial data is paramount. Yet in today’s increasingly connected factories and other industrial facilities, sharing data and keeping OPC servers online are critical concerns. However, whether in transit or at rest, these key OPC UA Security concepts will help you understand how your data is protected.
OPC UA stands for OPC Unified Architecture, which has been designed as platform-agnostic standard created to easily facilitate the secure exchange of data between industrial machines. OPC Unified Architecture (OPC UA) was designed with security in mind. One of the key OPC UA security concepts is ensuring the integrity and confidentially of messages through message encryption and signing.
Although this sounds fancy, the technologies OPC UA uses to achieve this have a direct impact on how end users interact with OPC UA products. Let’s explore this concept and outline details how to use it to make secure OPC UA connections.
There are three key layers within the OPC UA security model, including:
The transport layer is the first line of defense for the OPC UA. This layer focuses primarily on the IP address of the machine, as well as relevant ports. In addition, defenses such as user access lists or firewalls to manage connections exist here.
At the communication layer, the UPC UA client connects to the server and exchanges certificates to authenticate connections, as well as encrypt and sign messages sent.
In the UA application layer, this is where verification occurs that the user credentials accessing the Server have proper authority to access specific resources.
OPC UA uses an IT technology called X509 certificates for message signing and encryption. Signing means when your application receives a message, you can know exactly who sent it by checking the message signature. This protects against rogue entities sending your client or server bogus requests. Message encryption provides confidentiality by guaranteeing that only the receiver is able to read a message. So how do X509 certificates provide OPC UA applications with message signing and encryption?
Key OPC UA security concepts can be understood by taking a closer look at key security certificate functions:
Using a private key, the OPC UA message signing validates access. The application uses a private key to generate messages that can be validated by the public key certificate, thus establishing communications integrity.
OPC UA uses a public key to encrypt a message that can only be decrypted when the related private key is entered.
Quickly establish trust by checking the audit information generated by each OPA UA certification including the application, date generated, user, what the certificate is for, validity period, and other factors.
One of the key OPC UA security concepts is leveraging different forms of encryption. To better understand how this works, let’s look at the two types of encryptions for OPC UA and how they work.
Each OPC UA server or client gets an X509 certificate that contains a public key for the world, a private application key, and information on who owns the certificate. Each of these keys, large prime numbers that are hard to guess, are used to decrypt one another.
Asymmetric encryption is a method that connects an OPC UA client to a server. The server and client exchange and verify public keys. After connecting, they create a secure channel and encrypt the messages – the client with the server’s public key and sign with their private key. This multiple layered approach allows robust verification./p>
OPC Unified Architecture has been part of a movement to create new standards that operate across platforms and offer next-level security. With OPC UA, each connection goes through host identification, authorization, and encryption by exchanging certificates. This automated process brings the latest in secure connections to the table.
When designing your OPC UA security model, keep a few strategic questions to ask include:
That’s it. By making just a few key choices, you can ensure that your most important industrial automation data is protected. Since, setting up trust relationships between every client and server can be a bit of a burden at times, automation is key.
Exploring OPC UA Security Concepts
Exploring OPC UA - Key Concepts of a Layered Security Model