Keypoints:

Current system provides no actual security from the actual threats that affect almost everyone. But we can use cryptography concepts & systemic knowledge to implement layers on top of existing networks that do that. There are various parts to that, but a key stumbling block remains – how do you securely set up digital links of distributed key trust in the first place? I believe that a combination of software, a cheap hardware gidget of some type (one built in +/- 1 removable dongle per machine) + human okay could securely setup links between real people that communicate, & given them power to delegate secondary trust, ala PGP, and trust for stuff owned by who they trust, etc. Details, details…always important, but here the more crucial step is to agree about what you are actually trying to do & what counts as a good solution.

Hope for simplistic hardware to resist tampering:

a) no need for any source outside of the hardware unit to know the private key value

b) low performance needs by the standards of modern silicon – in functionality, speed, & duty cycles

c) can be designed as 1 time activation & 1 time auto-destruction if that is desired

Hiding backdoors in a device like that would be tricky to hide. Experts looking would notice if they were there in short order.