[Feature request] Singning messages and verifying signed messages

[NotRustyBot]

I suggest adding 2 new functions to the tool:
one to sign a message using sender's private key
and another to verify a signed message using sender's public key
This is commonly used to verify the sender's identity by anyone who has their public key.

[aliceandbob-io]

Thanks for the suggestion @NotRustyBot. I fully agree, these two features are already in the pipeline! 👍