Interesting, never done firmware, but plenty of backends and frontends. Besides the whole "do less and things get faster", I can't think of a single case where "simple" and "fast" is the same thing.

And I'd agree that "simple secure" is better than "complex secure" but you're kind of side-stepping what I said, what about "not secure at all", wouldn't that lead to simpler code? Usually does for me, especially if you have to pile it on top of something that is already not so secure, but even when taking it into account when designing from ground up.

Not really. `return 0` is the simplest program you could write, but it's not terribly useful. There's an underlying assumption that there's some purpose/requirement for the program to exist. Through that lens "secure" is just assumed as a requirement, and the simplest way to meet your requirements will usually still give you the fastest program too.

"Do less and things get faster" is a very wide class of fixes. e.g. you could do tons of per-packet decision making millions of times per second for routing and security policies, or you could realize the answer changes slowly in time, and move that to upfront work, separating your control vs data processing, and generally making it easier to understand. Or you could build your logic into your addressing/subnets and turn it into a simple mask and small table lookup. So your entire logic gets boiled down to a table (incidentally why I can't understand why people say ipv6 is complex. Try using ipv4! Having more bits for addresses is awesome!).