Specify BIP 382: Segwit descriptors

Author: achow101

README.mediawiki

@@ -1064,6 +1064,13 @@ Those proposing changes should consider that ultimately consent may rest with th
 | Pieter Wuille, Andrew Chow
 | Informational
 | Draft
+|-
+| [[bip-0382.mediawiki|382]]
+| Applications
+| Segwit Output Script Descriptors
+| Pieter Wuille, Andrew Chow
+| Informational
+| Draft
 |}
 
 <!-- IMPORTANT!  See the instructions at the top of this page, do NOT JUST add BIPs here! -->

bip-0380.mediawiki

@@ -246,4 +246,10 @@ This Table lists all available Script expressions and the BIPs specifying them.
 |-
 | <tt>sh(SCRIPT)</tt>
 | [[bip-0381.mediawiki|381]]
+|-
+| <tt>wpkh(KEY)</tt>
+| [[bip-0382.mediawiki|382]]
+|-
+| <tt>wsh(SCRIPT)</tt>
+| [[bip-0382.mediawiki|382]]
 |}

bip-0381.mediawiki

@@ -46,7 +46,7 @@ The output script produced is:
 
 ===<tt>pkh()</tt>===
 
-The <tt>pkh(KEY)</tt> expression can be used as a top level expression, or inside of a <tt>sh()</tt> descriptor.
+The <tt>pkh(KEY)</tt> expression can be used as a top level expression, or inside of either a <tt>sh()</tt> or <tt>wsh()</tt> descriptor.
 It takes a single key expression as an argument and produces a P2PKH output script.
 Depending on the higher level descriptors, there may be restrictions on the type of public keys that can be included.
 Such restrictions will be specified by those descriptors.

bip-0382.mediawiki

@@ -0,0 +1,70 @@
+<pre>
+  BIP: 382
+  Layer: Applications
+  Title: Segwit Output Script Descriptors
+  Author: Pieter Wuille <[email protected]>
+          Andrew Chow <[email protected]>
+  Comments-Summary: No comments yet.
+  Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0382
+  Status: Draft
+  Type: Informational
+  Created: 2021-06-27
+  License: BSD-2-Clause
+</pre>
+
+==Abstract==
+
+This document specifies <tt>wpkh()</tt>, and <tt>wsh()</tt> output script descriptors.
+<tt>wpkh()</tt> descriptors take a key and produces a P2WPKH output script.
+<tt>wsh()</tt> 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: <tt>wpkh()</tt>, and <tt>wsh()</tt>.
+
+===<tt>wpkh()</tt>===
+
+The <tt>wpkh(KEY)</tt> expression can be used as a top level expression, or inside of a <tt>sh()</tt> descriptor.
+It takes a single key expression as an argument and produces a P2WPKH output script.
+Only keys which are/has compressed public keys can be contained in a <tt>wpkh()</tt> expression.
+
+The output script produced is:
+<pre>
+OP_0 <KEY_hash160>
+</pre>
+
+===<tt>wsh()</tt>===
+
+The <tt>wsh(SCRIPT)</tt> expression can be used as a top level expression, or inside of a <tt>sh()</tt> descriptor.
+It takes a single script expression as an argument and produces a P2WSH output script.
+<tt>wsh()</tt> 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 <tt>SCRIPT</tt> argument to <tt>wsh()</tt>.
+Any key expression found in any script expression contained by a <tt>wsh()</tt> expression must only produce compressed public keys.
+
+The output script produced is:
+<pre>
+OP_0 <SCRIPT_sha256>
+</pre>
+
+==Test Vectors==
+
+TBD
+
+==Backwards Compatibility==
+
+<tt>wpkh()</tt>, and <tt>wsh()</tt> descriptors use the format and general operation specified in [[bip-0380.mediawiki|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 Implemntation==
+
+<tt>wpkh()</tt>, and <tt>wsh()</tt> descriptors have been implemented in Bitcoin Core since version 0.17.