This article rubs me the wrong way, because the number 1 problem I see when people implement crypto is that they don't have a well defined threat model or under

This article rubs me the wrong way, because the number 1 problem I see when people implement crypto is that they don't have a well defined threat model or understand how cryptography can assist them in addressing threats. The issue is not so much that there might be a flaw in their implementation -- indeed you should use reviewed libraries instead of rolling your own to avoid flaws -- this is not specific to crypto, it's just as much true for IO libraries or memory management libraries as it is for crypto. But what makes crypto unique is that cryptographic algorithms have very strict, well-defined, limited behaviors and there is generally a big gap between what people want to accomplish "don't let an attacker see this file" and what crypto will actually do for them "encrypt the file" and very often the use of crypto doesn't end up creating much value. Here, people do think cryptography is some kind of dark magic, where they can "secure" something just by encrypting it, and it's incredibly frustrating to have to implement cargo cult crypto that doesn't add much in the way of real security just because a PO views encryption as an end in itself -- e.g. as a feature.