You can't sign stuff without crypto (unless you mean by hand, on paper). Cryptographic signatures by design involve cryptography.

I know what you both meant, just playing with words, sorry. I just hope now that the dust has settled, we can go back to the world where "crypto" meant "cryptography", not anything else[1]

[1] https://www.cryptoisnotcryptocurrency.com/

Sure. I just mentioned crypto because that's what I'm familiar with, and there's already some infrastructure in place to facilitate it. But you will likely need to sign messages posted online - crypto or with your encryption key.