[bitcoin-dev] BIP draft: Merkelized Abstract Syntax Tree

[jl2012 at xbt.hk]

BIP draft: https://github.com/jl2012/bips/blob/mast/bip-mast.mediawiki
Reference implementation:
https://github.com/jl2012/bitcoin/commit/f335cab76eb95d4f7754a718df201216a49
75d8c

This BIP defines a new witness program type that uses a Merkle tree to
encode mutually exclusive branches in a script. This enables complicated
redemption conditions that are currently not possible, improves privacy by
hiding unexecuted scripts, and allows inclusion of non-consensus enforced
data with very low or no additional cost.

The reference implementation is a small and simple patch on top of BIP141
(segwit), however, I have no intention to push this before segwit is
enforced. Instead, I hope the MAST will come with many new op codes,
particularly Schnorr signature.