Today Nunchuk Wallet releases support for fully generalized Miniscript use, bringing a degree of flexibility and control to their users not seen before.
For those unfamiliar with Miniscript, it is a policy language invented by Core developer and former Maintainer Pieter Wuille to make the creation of customized Bitcoin scripts easier and safer. Miniscript takes the most commonly used pieces of Bitcoin script, i.e. signature locks, timelocks, hashlocks, etc. and creates a “higher level” programming language for users to create custom scripts.
This higher level language is designed to be safely analyzable and composable, meaning that once users create a customized script they can be sure that it will behave exactly how they expect it to.
Nunchuk provides two basic templates users can use, simply needing to fill in the keys they wish to use in the wallet. One is a decaying multisig, where after a timelock expires less keys are required to spend in order to ensure that key loss does not result in losing funds. The other is an expanding multisig, where over time other keys can sign for a transaction beyond the core key set. I.e. initially a 2-of-2 is required, but after a timelock a third key can sign instead.
In addition to these basic templates, more advanced users can import any custom Miniscript template they have created themselves.
Miniscript templates can be applied to both Native Segwit wallets as well as Taproot wallets.
Out of the gate, the following hardware wallets will support Native Segwit Miniscript: Coldcard, Tapsigner, Blockstream Jade, and Ledger.
The following will support Taproot Miniscript: Coldcard and Ledger.
MuSig2 use with Miniscript will be limited to software only keys for the time being.
Nunchuk’s end-to-end encrypted communication function has full support for Miniscript templates, allowing collaboration between users in constructing and using template based wallets.
In addition, Nunchuk has compiled a 101 Technical Guide for users who wish to make use of Miniscript in their wallets. For those more inclined to dive into the nuts and bolts themselves, here is also a website put together by Pieter Wuille with a breakdown of Miniscript itself and some basic tools.
