BIP: 384 source Layer: Applications Title: combo() Output Script Descriptors Author: Pieter Wuille <firstname.lastname@example.org> Andrew Chow <email@example.com> Comments-Summary: No comments yet. Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0384 Status: Draft Type: Informational Created: 2021-06-27 License: BSD-2-Clause
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This document specifies combo() output script descriptors. These take a key and produce P2PK, P2PKH, P2WPKH, and P2SH-P2WPKH output scripts if applicable to the key.
This BIP is licensed under the BSD 2-clause license.
In order to make the transition from traditional key based wallets to descriptor based wallets easier, it is useful to be able to take a key and produce the scripts which have traditionally been produced by wallet software.
A new top level script expression is defined: combo(KEY). This expression can only be used as a top level expression. It takes a single key expression as an argument and produces either 2 or 4 output scripts, depending on the key. A combo() expression always produces a P2PK and P2PKH script, the same as putting the key in both a pk() and a pkh() expression. If the key is/has a compressed public key, then P2WPKH and P2SH-P2WPKH scripts are also produced, the same as putting the key in both a wpkh() and sh(wpkh()) expression.
combo() descriptors use the format and general operation specified in 380. As this is a wholly new descriptor, it is not compatible with any implementation. However the scripts produced are standard scripts so existing software are likely to be familiar with them.
combo descriptors have been implemented in Bitcoin Core since version 0.17.