You have several ways to deal with trust issues in hardware:

1. Monitor hardware itself for bad behavior.

2. Monitor and restrict I/O to catch any leaks or evidence of attacks.

3. Use triple, diverse redundancy with voter algorithms for given HW chip and function.

4. Use a bunch of different ones while obfuscating what you're using.

5. Use a trusted process to make the FPGA, ASIC, or both.

I've mainly used No's 2-4 with No 5 being the endgame. I have a method for No 5 but can't publish it. Suffice it to say that almost all strategies involve obfuscation and shellgames where publishing it gives enemies an edge. kerckhoff's principle is wrong against nation-states: obfuscated and diversified combination of proven methods is best security strategy. Now, ASIC development is so difficult and cutting edge that knowing that the processes themselves aren't being subverted is likely impossible.

So, my [unimplemented] strategy focuses on the process, people, and key steps. I can at least give an outline as the core requirements are worth peer review and others' own innovations. We'd all benefit.

1. You must protect your end of the ASIC development.

1-1. Trusted people who won't screw you and with auditing that lets each potentially catch others' schemes.

1-2. Trusted computers that haven't been compromised in software or physically.

1-3. Endpoint protection and energy gapping of those systems to protect I.P. inside with something like data diodes used to release files for fabs.

1-4. Way to ensure EDA tools haven't been subverted in general or at least for you specifically.

2. CRITICAL and feasible. Protect the hand-off of your design details to the mask-making company.

3. Protect the process for making the masks.

3-1. Ensure, as in (1), security of their computers, tools, and processes.

3-2. Their interfaces should be done in such a way that they always do similar things for similar types of chips with same interfaces. Doing it differently signals caution or alarm.

3-3. The physical handling of the mask should be how they always do it and/or automated where possible. Same principle as 3-2.

3-4. Mask production company's ownership and location should be in a country with low corruption that can't compel secret backdoors.

4. Protect the transfer of the mask to the fab.

5. Protect the fab process, at least one set of production units, the same way as (3). Same security principles.

6. Protect the hand-off to the packaging companies.

7. Protect the packaging process. Same security principles as (3).

8. Protect the shipment to your customers.

9. Some of the above apply to PCB design, integration, testing, and shipment.

So, there you have it. It's a bit easier than some people think in some ways. You don't need to own a fab really. However, you do have to understand how mask making and fabbing are used, be able to observe that, have some control over how tooling/software are done, and so on. Plenty of parties and money involved in this. It will add cost to any project doing it which means few will (competitiveness).

I mainly see it as something funded by governments or private parties for increased assurance of sales to government and security-critical sectors. It will almost have to be subsidized by governments or private parties. My hardware guru cleverly suggested that a bunch of smaller governments (eg G-88) might do it as a differentiator and for their own use. Pool their resources.

It's a large undertaking regardless. Far as specifics, I have a model for that and I know one other high-assurance engineer with one. Most people just do clever obfuscation tricks in their designs to detect modifications or brick the system upon their use with optional R.E. of samples. I don't know those tricks and it's too cat n mouse for me. I'm focused at fixing it at the source.

EDIT: I also did another essay tonight on cost of hardware engineering and ways to get it down for OSS hardware. In case you're interested:

https://news.ycombinator.com/item?id=10468534