Signing is a subset of encryption, so it's not correct to say that no encryption is used in the protocol.

Is it not fair to say that signing is a subset of cryptography, just like encryption is a subset of cryptography? Wikipedia says (to me) that signing is not encryption: "In cryptography, encryption is the process of encoding messages (or information) in such a way that eavesdroppers or hackers cannot read it, but that authorized parties can." Encryption,

*per se*, seems to be the opposite of how the blockchain works (everybody sees every transaction).

That is not a good definition, encryption is basically just a mathematical function that takes plaintext and a key as inputs. With public key cryptography you have two keys and what one key encrypts the other key decrypts.

What we call encryption means using a public key to convert a message to cyphertext. Signing is the exact same mathematical function, except the private key is used and the data which is encrypted is the hash of a message instead of the message itself.