Three companies and a protocol stack
The internet was designed to route around failure. A large slice of it now routes through a handful of providers, and the failures that produces are not the ones the design had in mind.
resilience
Time and position became contested inputs
Half the infrastructure in this notebook assumes it can ask the sky what time it is. Jamming and spoofing of satellite navigation are now routine over large parts of Europe and the Middle East, which turns a free, assumed-correct input into something an adversary writes. The engineering response is holdover, and almost nobody has specified it.
