I agree with Lorenzo Franceschi-Bicchierai, “Cryptocurrencies aren’t ‘crypto’“:

Lately on the internet, people in the world of Bitcoin and other digital currencies are starting to use the word “crypto” as a catch-all term for the lightly regulated and burgeoning world of digital currencies in general, or for the word “cryptocurrency” — which probably shouldn’t even be called “currency,” by the way.

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To be clear, I’m not the only one who is mad about this. Bitcoin and other technologies indeed do use cryptography: all cryptocurrency transactions are secured by a “public key” known to all and a “private key” known only to one party­ — this is the basis for a swath of cryptographic approaches (known as public key, or asymmetric cryptography) like PGP. But cryptographers say that’s not really their defining trait.

“Most cryptocurrency barely has anything to do with serious cryptography,” Matthew Green, a renowned computer scientist who studies cryptography, told me via email. “Aside from the trivial use of digital signatures and hash functions, it’s a stupid name.”