BIP 382: Segwit Output Script Descriptors

  BIP: 382
Layer: Applications
Title: Segwit Output Script Descriptors
Author: Pieter Wuille <[email protected]>
Ava Chow <[email protected]>
Comments-Summary: No comments yet.
Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP 382
Status: Final
Type: Informational
Created: 2021-06-27
License: BSD-2-Clause
Requires: 380

Abstract

This document specifies wpkh() , and wsh() output script descriptors. wpkh() descriptors take a key and produces a P2WPKH output script. wsh() descriptors take a script and produces a P2WSH output script.

Copyright

This BIP is licensed under the BSD 2-clause license.

Motivation

Segregated Witness added 2 additional standard output script formats: P2WPKH and P2WSH. These expressions allow specifying those formats as a descriptor.

Specification

Two new script expressions are defined: wpkh() , and wsh() .

wpkh()

The wpkh(KEY) expression can be used as a top level expression, or inside of a sh() descriptor. It takes a single key expression as an argument and produces a P2WPKH output script. Only keys which are/have compressed public keys can be contained in a wpkh() expression.

The output script produced is:

OP_0 <KEY_hash160>

wsh()

The wsh(SCRIPT) expression can be used as a top level expression, or inside of a sh() descriptor. It takes a single script expression as an argument and produces a P2WSH output script. wsh() expressions also create a witnessScript which is required in order to spend outputs which use its output script. This redeemScript is the output script produced by the SCRIPT argument to wsh() . Any key expression found in any script expression contained by a wsh() expression must only produce compressed public keys.

The output script produced is:

OP_0 <SCRIPT_sha256>

Test Vectors

Valid descriptors followed by the scripts they produce. Descriptors involving derived child keys will have the 0th, 1st, and 2nd scripts listed.

• wpkh(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)
  • 00149a1c78a507689f6f54b847ad1cef1e614ee23f1e
• wpkh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)
  • 00149a1c78a507689f6f54b847ad1cef1e614ee23f1e
• wpkh([ffffffff/13']xprv9vHkqa6EV4sPZHYqZznhT2NPtPCjKuDKGY38FBWLvgaDx45zo9WQRUT3dKYnjwih2yJD9mkrocEZXo1ex8G81dwSM1fwqWpWkeS3v86pgKt/1/2/0)
  • 0014326b2249e3a25d5dc60935f044ee835d090ba859
• wpkh([ffffffff/13']xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH/1/2/*)
  • 0014326b2249e3a25d5dc60935f044ee835d090ba859
  • 0014af0bd98abc2f2cae66e36896a39ffe2d32984fb7
  • 00141fa798efd1cbf95cebf912c031b8a4a6e9fb9f27
• sh(wpkh(xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi/10/20/30/40/*'))
  • a9149a4d9901d6af519b2a23d4a2f51650fcba87ce7b87
  • a914bed59fc0024fae941d6e20a3b44a109ae740129287
  • a9148483aa1116eb9c05c482a72bada4b1db24af654387
• sh(wpkh(xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi/10/20/30/40/*h))
  • a9149a4d9901d6af519b2a23d4a2f51650fcba87ce7b87
  • a914bed59fc0024fae941d6e20a3b44a109ae740129287
  • a9148483aa1116eb9c05c482a72bada4b1db24af654387
• wsh(pkh(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1))
  • 0020338e023079b91c58571b20e602d7805fb808c22473cbc391a41b1bd3a192e75b
• wsh(pkh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd))
  • 0020338e023079b91c58571b20e602d7805fb808c22473cbc391a41b1bd3a192e75b
• wsh(pk(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1))
  • 00202e271faa2325c199d25d22e1ead982e45b64eeb4f31e73dbdf41bd4b5fec23fa
• wsh(pk(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd))
  • 00202e271faa2325c199d25d22e1ead982e45b64eeb4f31e73dbdf41bd4b5fec23fa
• sh(wsh(pkh(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)))
  • a914b61b92e2ca21bac1e72a3ab859a742982bea960a87
• sh(wsh(pkh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)))
  • a914b61b92e2ca21bac1e72a3ab859a742982bea960a87

Invalid descriptors with descriptions

• Uncompressed public key in wpkh() : wpkh(5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss)
• Uncompressed public key in wpkh() : sh(wpkh(5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss))
• Uncompressed public key in wpkh() : wpkh(04a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd5b8dec5235a0fa8722476c7709c02559e3aa73aa03918ba2d492eea75abea235)
• Uncompressed public key in wpkh() : sh(wpkh(04a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd5b8dec5235a0fa8722476c7709c02559e3aa73aa03918ba2d492eea75abea235))
• Uncompressed public keys under wsh() : wsh(pk(5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss))
• Uncompressed public keys under wsh() : wsh(pk(04a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd5b8dec5235a0fa8722476c7709c02559e3aa73aa03918ba2d492eea75abea235))
• wpkh() nested in wsh() : wsh(wpkh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd))
• wsh() nested in wsh() : wsh(wsh(pkh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)))
• wsh() nested in wsh() : sh(wsh(wsh(pkh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd))))
• Script in wpkh() : wpkh(wsh(pkh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)))
• Key in wsh() : wsh(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)

Backwards Compatibility

wpkh() , and wsh() descriptors use the format and general operation specified in 380 . As these are a wholly new descriptors, they are not compatible with any implementation. However the scripts produced are standard scripts so existing software are likely to be familiar with them.

Reference Implementation

wpkh() , and wsh() descriptors have been implemented in Bitcoin Core since version 0.17.

View on GitHub

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