Explained the basic crypto behind modern E-cash and the Cashu protocol proposed by nostr:npub12rv5lskctqxxs2c8rf2zlzc7xx3qpvzs3w4etgemauy9thegr43sf485vg.

I fast coded a cashu wallet in stage, but you can check a more structured material at https://github.com/edilmedeiros/cashu-workshop

Feedback and PRs are super welcome to make this the best introductory cashu workshop/workbook.