Yes, that's the idea. Force specialization in the attack sphere, reduce the attacker population with prerequisite knowledge as an entry barrier, simultaneously shrinking the targetable hosts.

Yes, I get that electronic signaling is electronic signaling, and none of it is actually different, at the transmission layer. It's just more DSP and more fast fourier transforms under the hood.

Yes, technical barriers can be eroded with adapters and facades, but it's an added cost to attack, and reduces detective work in that you have to know someone to jump the learning curve and enter the attack envelope. That means detective work can happen within a smaller social graph, and that alone becomes a deterent from sharing information, because everything becomes need-to-know, and insider awareness is a give away for inside jobs.

It's also easier to stamp out, and ostracize insiders, if they have loose lips or have a tendency to lend and give away the car keys.

Not everything needs to be as cheesy as Encryption DRM for optical movie disks and video games. For critical infrastructure safety is important enough to warrant independent military-grade safe guards.

Do military protocols fail? Yes, we have the enigma machines sitting in enough museums to prove it.

This in not an XKCD "too many standards can be solved with one more standard" concept. Isolation and specialization can be effective defense concepts.

"Isolation and specialization can be effective defense concepts."

Thank you - appreciated.

Many people (unwittingly ?) argue against defense-in-depth because they look at individual layers of the defense and declare them inadequate. They are always correct.

What they are missing is that nobody ever proposed only using (port knocking, or stack obfuscation, or fake login banners, or whatever). They are always additive layers of security on top of the existing set of best practices.

> e-mail taking a week or more to make it across the Atlantic

Any reading material behind this? Really interesting, would like to read up on what caused such a delay

In books, probably. But this was before the web, so I don't know if there are any authoritative web sites about it. You might check the old late 1970's and early 1980's computer magazines on archive.org.

A large part of the delay is that messages were transmitted in a store-and-forward scheme (often via uucp). And most machines didn't send messages more than once a day because connectivity was expensive and measured in dollars per minute. And when they did connect to the next machine, it was usually not a very long hop. Sometimes one part of a campus to another. Or to a computer in the next town.

I really don't know exactly how the messages crossed oceans. Satellite transmission would have been unthinkable. My guess is that eventually they hit some big east coast computing center like MIT or BBN and went via undersea cable, but that's speculation.

I ran a node of one of the pre-intenet networks. Like most of the other nodes, it was connected via 150 or 300 baud dialup modem. Later there were a few 1200's, but they were rare.

My node was important because it was oddly located so that it could span two states and two area codes without incurring toll charges. That made it very busy, so the early morning (2am) message transfer sometimes took a couple of hours.

I tried to write a couple of articles about the old American dialup networks on Wikipedia once, but someone in another country deleted them saying they didn't exist because he'd never heard of it and if there was no web site to link to as reference it didn't happen. I stopped contributing to Wikipedia after that.

UUCP links over 1200 baud modems, connecting only at night for cheap rates, but stymied by busy signals, down hosts, deep queues of other data, stalled daemons, out-of-date routing tables. Trans-oceanic links had high costs and limited available bandwidth, and priority queueing could impose quite a delay.