There have been several security threads recently. These have caused me to consider ways to obtain maximum code security.

We currently use security bits to block the reading of the flash. We also have patched every hole we could find in the ISP / IAP routines. And together, this should prevent the casual thief from getting the code.

Still, the code is in a flash, and any die can be cut open and its memory read by any failure analysis lab in a few weeks for a few thousand dollars.

But if I synthesize the program into gates, and use a few other layout encryption tricks, I can raise the cost of reverse engineering the code into years and millions of dollars.

The disadvantages for this approach are that the code is now hard encoded, it takes 8 weeks to get parts, and that it gets expensive for low volumes < 3K. At 10K units, it would probably add $2 to the unit cost.

So, how much is security worth? Would this fly as a product?

This approach is also untestable, since any test program would divulge the code. We would have to have the user incorporate some sort of checksum calculator in their code, which would run (perhaps conditionally) at reset. Would that be a problem for the average user?

I would be interested in hearing opinions on this. </marketing mode off>