How Potting Protects Against Reverse Engineering

Conformal coating and potting are widely used techniques to safeguard printed circuit boards (PCBs) and cable connections. They are particularly crucial for components operating in damp, dusty outdoor settings or internal environments with caustic solutions or organic fluids.

Both processes are complex, with numerous production variables. Unlike the protective films provided by conformal coating, potting involves fully encasing a PCB in a resin container that integrates seamlessly as a crucial component of the unit.

Conformal coatings have become the predominant choice over potting for safeguarding PCBs. However, the selection between the two depends heavily on project-specific needs, including budget constraints, coating techniques and project timelines. Mitigating the risk of reverse engineering stands out as a critical consideration in this regard.

What Is Reverse Engineering?                 

Disassembling a manufactured object to determine its design and working processes, to duplicate or enhance it, is the essence of reverse engineering. Reverse engineering is a versatile practice utilized across various domains like biological, chemical, and organic matter. It is frequently employed in computer hardware and software to extract intricate and relevant information about a device’s operation and functionality. This process analyzes machine code and source code, translating them into program language statements.

Reverse engineering can prove beneficial by preserving valuable components of older systems or facilitating compatibility among diverse computers. It serves as a potent tool against malware, while also aiding in the documentation of legacy systems.

Often, however, reverse engineering’s objective is analyzing the PCB’s smart card for unlicensed appropriation of the object, its purpose and value, basically stealing both the product and the intellectual property that created it. Methods of combatting destructive reverse engineering during PCB manufacture include:

• Bus scrambling
• Positioning sensors within the PCB to detect/prevent reverse engineering
• Resituating memory positions to disguise keys/operations.

These techniques can be built in during the PCB original design and construction. Potting the PCB during manufacture represents an additional means of further protecting against unwanted reverse engineering.

Utilizing Potting for Enhanced Reverse Engineering Security

PCB assemblies requiring reverse engineering security benefit from potting encapsulation. A dual-phased process, potting uses a “pot” in the form of a case, shell or similar enclosure, to completely cover an electronic/electrical device, protecting it from the surrounding environment. Usually, a liquid potting compound is poured into the casing, surrounding the enclosed PCB, ultimately becoming an integral part of the final assembly. Because of this, potting is a very clear choice for boards requiring reliable, long-term impact resistance or durability in the face of persistent and turbulent mechanical abrasion. Compared to conformal coating, protection against tin whiskers also improves with potting, as does the assembly’s overall functional lifespan.

These same resistant qualities inform potting’s value for protecting against reverse engineering.  Potting encapsulation offers a thicker and more robust solution to prolong the operational lifespan of PCBs, ensuring their sustained functionality over extended periods. Potting significantly enhances protection against security threats like reverse engineering or tampering with the assembly’s function and design features. Potted coatings made from epoxy or urethane resins are largely impervious to the effects of most chemical solvents, substantially increasing the difficulty of penetrating the PCB encasement or otherwise accessing the device for reverse engineering. Moreover, the use of pigmented potting material conceals the components housed within the encasement, effectively shielding the circuit board and its elements from casual reverse-engineering endeavors, examination and potential theft.

Thermo-setting plastics, silicone rubber gels and similar lower glass-transition temperature (Tg) compounds are also frequently used for potting PCBs. Nevertheless, the majority of potting applications rely on epoxy due to its advantageous combination of adhesive, electrical, mechanical and thermal properties. Selection of the wrong materials can generate undue structural stress or heat, which can weaken the potted protection, potentially aiding reverse engineering incursions. Thus, care must be taken selecting potting materials appropriate to the PCB’s function and operational environment.
In general, however, potting cases are secure, offer dielectric protection, and safeguard the PCB from the polluting effects of acids, bases, corrosion, salt and most solvents, as well as deterring reverse engineering. The extremely thick block coverage engendered by potting supports post-production conditions where assembly privacy and security are necessary to product performance. The potting case effectively obscures a PCB’s circuit diagram, making it far less visible and susceptible to reverse engineering.

Potting entails fully enclosing an electronic assembly to provide optimal security against unauthorized access and modification. These wrongful alterations could potentially hamper the board’s functionality while still allowing it to operate. Such industrial espionage could undermine a product’s performance, giving a competitive advantage to rivals offering similar PCBs. When executed correctly, potted encapsulation can guarantee that any attempts to breach the protective barrier and reach the PCB will result in the destruction of the circuit itself, effectively thwarting deceptive reverse engineering tactics.