📥 [Analysis] Graftroot: how delegating signatures allows for near-infinite spending variations- Aaron van Wirdum

As an alternative to Bitcoin ($BTC) smart contract protocol Taproot, Bitcoin Core developer Gregory Maxwell has put forward Graftroot, a similar system to Taproot that increases contract flexibility while lowering data storage. Like Taproot, Graftroot uses 'threshold' public keys and signatures to mask smart contracts into regular Bitcoin transactions. In the protocol, the parties sign alternative scripts, the possible conditional outcomes of the contract, which can occur if a 'cooperative close' is not found. A cooperative close is when both parties accept the contract as it stands. If a cooperative close does not occur, the alternative scripts come into play: the user whose alternative script lines up with the contract first--say a certain amount of time passed or combination with a secret number--is awarded the coins. The upside of Graftroot is the endless alternative scripts available; the downside is the high level of party interaction necessary to establish the contract and the need for key storage for each alternative script. As of now, Graftroot sits behind Schnorr and Taproot for softfork deployment.