Epoxy Covered PCBAs Means to prevent hacking?

By "hacking" do you mean altering the performance of the board or something else?

This reminds me of something I saw a while back. Better termed counterfeiting than hacking, it may have some relevance to what your friend is trying to do.

The problem was that a large automotive electronics remanufacturer was being taken to the cleaners with a large quantity of bogus field returns. It turned out that this was the byproduct of warranty work being performed by their dealers. The dealers were taking subassemblies and components from certified replacement assemblies to trouble shoot and fix the more expensive entire modules. Then to avoid paying for the cannibalized assemblies they replaced the missing components with the switched faulty ones and claimed that when the units were installed they never worked. Apparently many unscrupulous dealers were taking part in this practice and the cost to them was enormous.

They had tried all kinds of pot molding and encapsulation techniques to thwart this practice over the years, but found that in the long run this was only hurting themselves as they often had to rework these encapsulated boards themselves for various reasons. It was apparent that the cure was worse than the disease as many parts were scrapped in the process.

The best solution turned out to be getting rid of encapsulation and to place a direct part mark using a laser to etch a tiny 2D matrix code that corresponded to an encrypted code for each unique board and a corresponding code for each of it's mission critical components. The mark could only be read with a hand-held 2D reader once product was returned and the code referenced the original sequence in a confidential look-up table.

If a component was found to have been uncoded "switched" or it was proven that the core was altered with other non-conforming parts they could catch the culprit red handed and null their guarantee under a fraud clause in the dealers contract.

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