cj371

If you're so confident in your experts, maybe respond to my comment where I point out a major bug? https://news.ycombinator.com/item?id=21889302

The microcontroller isn't the only thing that matters in your design. For example, since you're dependant on the ADC for seeding the RNG, it'd be nice to know what is connected to those pins, which a schematic would reveal. I can't tell that just by looking through your clear epoxy.

Even if I did drill holes in the casing and probe components, I have no way of knowing if what I'm seeing is expected or not without a schematic.

Even if that analog pin provides a reasonable amount of entropy (which I'm skeptical of), you have a major bug: you're casting the ADC reading to a pointer, and then dereferencing it inside RNG.stir.

Let me say it again: you're taking an ADC reading (in the range of 0-1023) and accessing it as if it's a memory address.

To make things worse, addresses 0 through 1023 on the Kinetis you're using are the vector table. Take a look at that part of your firmware: it's extremely predictable, and only contains a small number of possible values.