So, in other words, exactly like algorithms then?
If you hire based on knowing how the the internet works (TLS, HTTP, BGP, whatever), then you'll be working with a bunch of people that understand how the internet works.
I know which team I'd rather join.
Now, if I'm hiring a sysop / devop / security engineer, it's going to be differently focused to some extent, but the same principles apply - core knowledge, communication, humility, ability to research.
(Admittedly, candidates are likely to have memorized the algorithm for reversing a binary tree since that is such a common interview question)
Exactly my point. Testing for "how to implement a known algorithm" is much the same as recalling facts about TLS. You're testing recall only.
If you are the interviewer, even if you are asking a standard "how to invert a binary tree" type algorithm question, you hold the cards to keep pushing the bounds for problem solving by extending the question.
i though like you before doing interviews
Some of the absolute best engineers that I've worked with take their time to wrap their heads completely around a problem before diving in. They aren't slow thinkers, but they aren't people who excel at these kinds of interviews either.
I've been doing interviews for a long time now and I find it more effective to surface strong opinions about things they've worked on -- good and bad.
I'm not hiring into a feature factory -- I don't care about fast cogs. I'm hiring people who care about what they do and giving them an environment to thrive in.
Reversing a binary tree on a whiteboard is certainly a bad question to ask. But I would argue, for all intends and purposes still a miles better indicator about future potential than if someone knows how/why TLS work. Yeah you can read that in a book. I can google it. Useless for interviews.
If you are hiring for a position that requires you to implement TLS, sure go for it. But that is not the rule. And what are you going to do after he has implemented TLS? Will he be able to work on something completely different?