> Security protocols have a short list of moving parts and trade offs and where to attack them. RNGs, key storage, key derivation, counters, and access modes, to name a few. They're only completely different to people who don't understand them.
Funny, I would have said that they only look very similar to one another to people who aren't deep enough in the weeds of a particular one.
Yes, they're ultimately all built out of the same building blocks. But just with these few you've mentioned, together with possibly having more than two actors in your system and corresponding privileged keys, the complexity of the aggregate protocol hockey sticks very quickly, and you absolutely can't reduce all problems to one another anymore.
Humans are made of atoms, yet when you're sick you go to a physician, not to a physicist.
> If you are using symmetric secrets in smart cards, you're using something within a degree of EMV
Oh, absolutely not. Sorry, but with this statement you show that you aren't familiar with other protocols in this space. There are so many smartcard (and adjacent, e.g. stored-value cards like MIFARE) protocols that use symmetric keys, yet don't share any of EMVs historical problems. I mean, even GlobalPlatform itself uses symmetric cryptography!
That's like saying that SSH and TLS are very similar protocols, since they both use asymmetric key exchanges to secure and authenticate a symmetrically-encrypted application layer channel.