SegWit: Bob, Alice and Trent meet Schnorr

Let’s say we have a transaction, and Bob, Alice and Trent must authorise it. In a Bitcoin network, this is defined as a “multisig” setup. Bob, Alice and Trent must then go away and create their own new “aggregated” signature, which will be their new public key for transactions. This is not efficient, and also reveals the Bob, Alice and Trent are working together. In an improved setup, we can define an n-from-m setup…