Is It Worth Encrypting Your PLC Code? Know-How Protection in Industrial Automation

Engineering teams often implement PLC code protection because they believe they should, not because they actually need to. The result is usually more problems, not more security.

In my experience with industrial automation systems, I have seen code protection create far more operational headaches than it prevents security breaches. Encrypted function blocks that cannot be troubleshooted during faults. Documentation gaps because protected code cannot be automatically documented. Password management failures that lock teams out of their own systems.

Meanwhile, the code being protected is typically standard industrial automation. Conveyor controls, pump sequences, temperature loops. Nothing proprietary. Nothing that any competent programmer could not recreate from scratch in a reasonable time.

The Reality Check Nobody Wants to Hear

Let me ask you something. If a competitor wanted to steal your automation system, what exactly would they need to copy?

Your PLC code is just the beginning. They would need to understand your process, replicate your hardware configuration, duplicate your mechanical systems, rebuild your electrical infrastructure, and somehow recreate the entire industrial environment that your code operates within.

Think about that for a moment. Even if someone obtained your complete PLC program, they would still need the HMI configuration, the drive parameters, the instrument calibrations, the piping and instrumentation diagrams, the mechanical drawings, and most importantly, the process knowledge that took years to develop.

They would need to understand why you chose that particular interlock sequence, why the delay timers are set to those specific values, and why certain equipment starts in that exact order. This knowledge exists in the heads of your operators, your maintenance technicians, and your process engineers. You cannot encrypt experience.

But here is the part that really makes code protection pointless: reverse engineering industrial systems is not as difficult as people imagine. Any competent engineer can observe your process in operation, study your SCADA screens, and recreate the control logic. Your SCADA system reveals far more about your process than your PLC code ever could.

SCADA shows the process flow, the control strategies, the alarm conditions, the operating parameters, and the relationships between different parts of your system. It displays this information in a logical, organized format that is much easier to understand than diving through ladder logic or function block diagrams. A few hours watching your SCADA screens during normal operation provides more insight into your process than weeks of studying encrypted PLC code.

In my career, I have never seen a case where stolen PLC code led to meaningful competitive disadvantage. I have seen dozens of cases where unnecessary code protection created expensive maintenance problems.

When Protection Actually Makes Sense

Before you assume I am completely against code protection, let me be clear. There are legitimate cases where encrypting PLC code makes business sense.

Machine builders who sell equipment globally often protect their control algorithms. When you are selling the same machine design to hundreds of customers, and your competitive advantage lies in the sophisticated control sequence you developed, protection makes sense. Your customers are buying the machine, not the right to reverse-engineer and reproduce your intellectual property.

Companies with genuinely proprietary processes might also justify code protection. If your automation system implements a chemical reaction sequence that took years of research to optimize, and that sequence represents significant competitive advantage, protection might be warranted.

But here is the key question: how many automation projects actually fall into these categories?

Most industrial automation implements well-established processes using standard control patterns. Conveyor systems, pump controls, temperature loops, safety interlocks, batch sequences. These are not trade secrets. They are engineering solutions to common industrial problems.

The Hidden Costs of Unnecessary Protection

Code protection introduces several practical problems that engineering teams often underestimate.

Troubleshooting becomes significantly more difficult when sections of your code are encrypted. When a production fault occurs, maintenance technicians cannot examine the logic that might be causing the problem. They cannot see the internal operations of protected function blocks, cannot monitor intermediate variables, and cannot understand the decision-making process that led to the fault condition.

This extends troubleshooting time and increases downtime costs. In my experience, the additional troubleshooting time typically costs more than the value of whatever intellectual property the protection was supposed to preserve.

Documentation becomes more complex when you have encrypted code sections. You cannot automatically generate complete documentation from your project when portions are protected. Manual documentation must be maintained separately, creating additional opportunities for errors and inconsistencies.

Personnel changes create significant risks when code is protected. If the person who implemented the protection leaves the company, and password management was not handled properly, you might find yourself unable to modify or troubleshoot your own automation system. This is not a theoretical concern – it happens more often than engineering teams expect.

Version control and backup procedures become more complicated when dealing with protected code. Standard backup and restore procedures might not preserve protection settings correctly, especially when moving between different versions of programming software.

TIA Portal Know-How Protection in Practice

TIA Portal provides several know-how protection options, but understanding their limitations is crucial for making informed decisions.

The most common protection method encrypts function blocks and data blocks with password protection. This prevents unauthorized users from viewing or modifying the protected content. However, the protection is not bulletproof. Determined individuals with sufficient expertise can often find ways around software-based protection methods.

More importantly, know-how protection in TIA Portal can affect system performance. Encrypted function blocks require additional processing overhead during execution. For most applications, this overhead is negligible, but in systems with tight timing requirements or heavy computational loads, the performance impact might be noticeable.

The protection also creates dependencies on specific software versions. Protected blocks created in one version of TIA Portal might not be fully compatible with future versions, potentially creating migration problems down the road.

Copy protection features can prevent unauthorized duplication of your program to other hardware, but this also makes legitimate hardware replacement more complex. When a CPU fails and needs to be replaced quickly to restore production, copy protection can add unnecessary complications to the recovery process.

Alternative Security Strategies That Actually Work

Instead of reflexively implementing code protection, consider security strategies that address real threats without creating operational problems.

Physical security often provides better protection than software encryption. Securing access to programming equipment, implementing proper network segmentation, and controlling who can connect to your automation systems address more realistic security threats than code theft.

Access control through user management systems provides granular control over who can view, modify, or download programs without the complications of encrypted code. TIA Portal supports sophisticated user access controls that can restrict specific individuals to specific areas of the program.

Proper contractual agreements often provide better intellectual property protection than technical measures. Employment contracts with appropriate non-disclosure and non-compete clauses, vendor agreements that clearly define intellectual property rights, and customer contracts that specify permitted uses of provided automation systems address the legal aspects of intellectual property protection.

Network security measures such as VPNs, firewalls, and secure remote access provide protection against unauthorized access to your automation systems without affecting the operability of the control code itself.

Making Rational Protection Decisions

When evaluating whether code protection makes sense for a particular project, a structured decision-making process helps cut through the assumptions and get to the real facts.

The first step would be identifying what intellectual property actually exists in the automation system. Is there genuinely proprietary control logic, or are we dealing with standard industrial automation practices? Often, this exercise alone reveals that there is nothing worth protecting.

Next would be evaluating the realistic threats. Who might want to steal this code, and what would they do with it? How much effort would be required to reverse-engineer the process even with access to the complete program? Usually, the threat assessment shows that the risk is much lower than initially perceived.

The third consideration would be calculating the costs of protection versus the value of what we are protecting. This includes the direct costs of implementing protection, the ongoing costs of managing passwords and documentation, and the potential costs of troubleshooting difficulties and operational disruptions.

Then would come considering alternative protection strategies that might provide better overall security with fewer operational complications.

Finally, the long-term implications need evaluation. How will protection affect system maintainability over the expected life of the automation system? How will it affect future upgrades and modifications?

In my experience, this systematic evaluation usually leads to the conclusion that code protection is unnecessary for most industrial automation applications.

When I Say No to Protection Requests

Part of providing honest consulting advice means sometimes telling clients that their requested solution is not in their best interest.

I regularly encounter requests for code protection on systems where it provides no meaningful benefit. Often, engineering teams want to encrypt function blocks implementing standard industrial processes using well-established control algorithms. There is no proprietary technology, no competitive advantage to protect, and no realistic threat of intellectual property theft.

In these situations, protection would make troubleshooting more difficult, documentation more complex, and maintenance more expensive, all while providing no actual security benefit.

Instead of implementing unnecessary protection, I help teams develop comprehensive security plans that address real threats. Network segmentation, improved access controls, proper backup procedures, and solid documentation standards provide better overall security without the operational complications of encrypted code.

Sometimes the most valuable service a consultant can provide is preventing clients from implementing solutions that will create more problems than they solve.