>It seems likely that it simply wasn't given any thought. Not so much that they did trust them, but that they didn't comprehend what could have been done, and so it never really bothered them that much.

To my knowledge, 20 years ago Russian security agencies were trying to inspect in depth any foreign computer hardware (as there is no other computer hardware existed back then or even today in Russia) that they were buying. Not that one is able to seriously inspect beyond the level of the plastic body of a chip, yet they tried at least :)

One is often able to inspect beyond that level.

https://duckduckgo.com/?q=semiconductor+decapsulation

The fact that these techniques do work fairly well for semiconductor reverse engineering is a reason that recent research on "stealthy dopant-level hardware Trojans" was scary.

http://www.iacr.org/workshops/ches/ches2013/presentations/CH...

Though maybe that's what your reference to the inability to "seriously" inspect chips refers to. :-)

This research produces optically indistinguishable ICs with different electrical properties, which hinders optical reverse engineering.

My impression is that there's still a semiconductor device reverse engineering technique which likely defeats this measure (FIB imaging)

https://en.wikipedia.org/wiki/Focused_ion_beam

as well as some other microscopy techniques that might conceivably detect these differences, but that it's more difficult and expensive overall compared to optical imaging.

I just saw on the cryptography mailing list that some researchers have succeeded in using both SEM and FIB to see the stealthy dopants:

https://eprint.iacr.org/2014/508

So maybe the dopants have to get even stealthier if they're to avoid expert semiconductor reverse engineers. :-)

That depends on your definition of "seriously" I guess. But there is no need to stop at the plastic. Have a look what the guys at chipworks are doing: http://www.chipworks.com

Also the Russians are traditionally quite good at reverse engeneering ;-) and they _did_ have their own domestic chips 20 years ago.

>they _did_ have their own domestic chips 20 years ago.

No. Not back then, not now. There hasn't been a chip there able to run Word/Excel/email. The best "native" chips are the 30 year old ones, with some updates, in the anti-ICBM systems.