This is perhaps the most important tool used in cryptocurrency. A signature is, you, right? But how will we, just as we do with that physical paper signature, verify you as you? We start with four very basic assumptions:

• Our digital signature needs to verify you are you and do it with 100% accuracy every time
• It should be non-forgeable and non-copyable
• Non-repudiation, meaning if you signed it, you own it, and it was you and no one else but you
• Your signature is your public and private key