Merge pull request #2239 from guggero/descriptors-bugfix

BIP-{383,386,389,390}: fix small issues and discrepancies

bip-0383.mediawiki

@@ -39,7 +39,11 @@ Depending on the higher level descriptors, there may be restrictions on the type
 
 Depending on the higher level descriptors, there are also restrictions on the number of keys that can be present, i.e. the maximum value of <tt>n</tt>.
 When used at the top level, there can only be at most 3 keys.
-When used inside of a <tt>sh()</tt> expression, there can only be most 15 compressed public keys (this is limited by the P2SH script limit).
+When used inside of a <tt>sh()</tt> expression, the output script produced is the redeem script,
+which is pushed as a single element in the spending scriptSig and must therefore not exceed the
+520 byte limit on the size of a script element.
+This allows at most 15 compressed public keys, or at most 7 uncompressed ones, as an uncompressed
+key takes 66 bytes of the script rather than 34.
 Otherwise the maximum number of keys is 20.
 
 The output script produced will be

bip-0386.mediawiki

@@ -97,6 +97,7 @@ Valid descriptors followed by the scripts they produce. Descriptors involving de
 ** <tt>512017cf18db381d836d8923b1bdb246cfcd818da1a9f0e6e7907f187f0b2f937754</tt>
 * <tt>tr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd,{pk(xprvA2JDeKCSNNZky6uBCviVfJSKyQ1mDYahRjijr5idH2WwLsEd4Hsb2Tyh8RfQMuPh7f7RtyzTtdrbdqqsunu5Mm3wDvUAKRHSC34sJ7in334/0),{{pk(xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL),pk(02df12b7035bdac8e3bab862a3a83d06ea6b17b6753d52edecba9be46f5d09e076)},pk(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)}})</tt>
 ** <tt>512071fff39599a7b78bc02623cbe814efebf1a404f5d8ad34ea80f213bd8943f574</tt>
+* <tt>tr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd,pkh(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1))</tt>
 
 Invalid Descriptors
 
@@ -104,7 +105,6 @@ Invalid Descriptors
 * Uncompressed public key: <tt>tr(04a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd5b8dec5235a0fa8722476c7709c02559e3aa73aa03918ba2d492eea75abea235)</tt>
 * <tt>tr()</tt> nested in <tt>wsh</tt>: <tt>wsh(tr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd))</tt>
 * <tt>tr()</tt> nested in <tt>sh</tt>: <tt>sh(tr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd))</tt>
-* <tt>pkh()</tt> nested in <tt>tr</tt>: <tt>tr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd, pkh(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1))</tt>
 
 ==Backwards Compatibility==
 
@@ -113,8 +113,9 @@ As these are a set of wholly new descriptors, they are not compatible with any i
 However the scripts produced are standard scripts so existing software are likely to be familiar with them.
 
 Tree Expressions are largely incompatible with existing script expressions due to the restrictions in those expressions.
-As of 2021-06-27, the only allowed script expression that can be used in a tree expression is <tt>pk()</tt>.
+Of the script expressions that existed when this BIP was written, only <tt>pk()</tt> can be used in a tree expression.
-However there will be future BIPs that specify script expressions that can be used in tree expressions.
+Script expressions specified since then that can be used in a tree expression are the Miniscript expressions of [[bip-0379.md|379]], which
+include a <tt>pkh()</tt> fragment, and the <tt>multi_a()</tt> and <tt>sortedmulti_a()</tt> expressions of [[bip-0387.mediawiki|387]].
 
 ==Reference Implementation==
 

bip-0389.mediawiki

@@ -38,12 +38,12 @@ For extended keys and their derivations paths in a Key Expression, BIP 380 state
 This is modified to state:
 
 * <tt>xpub</tt> encoded extended public key or <tt>xprv</tt> encoded extended private key (as defined in BIP 32)
-** Followed by zero or more <tt>/NUM</tt> (may be followed by <tt>h</tt>, <tt>H</tt>, or <tt>'</tt> to indicate a hardened step) path elements indicating BIP 32 derivation steps to be taken after the given extended key.
+** Followed by zero or more <tt>/NUM</tt> (may be followed by <tt>h</tt> or <tt>'</tt> to indicate a hardened step) path elements indicating BIP 32 derivation steps to be taken after the given extended key.
-** Followed by zero or one <tt>/<NUM;NUM</tt> (each <tt>NUM</tt> may be followed by <tt>h</tt>, <tt>H</tt>, or <tt>'</tt> to indicate a hardened step) path element indicating a tuple of BIP 32 derivation steps to be taken after the given extended key.
+** Followed by zero or one <tt>/<NUM;NUM</tt> (each <tt>NUM</tt> may be followed by <tt>h</tt> or <tt>'</tt> to indicate a hardened step) path element indicating a tuple of BIP 32 derivation steps to be taken after the given extended key.
-*** Followed by zero or more <tt>;NUM</tt> (may be followed by <tt>h</tt>, <tt>H</tt>, or <tt>'</tt> to indicate a hardened step) additional tuple values of BIP 32 derivation steps
+*** Followed by zero or more <tt>;NUM</tt> (may be followed by <tt>h</tt> or <tt>'</tt> to indicate a hardened step) additional tuple values of BIP 32 derivation steps
 *** Followed by a single <tt>>/</tt>
-** Followed by zero or more <tt>/NUM</tt> (may be followed by <tt>h</tt>, <tt>H</tt>, or <tt>'</tt> to indicate a hardened step) path elements indicating BIP 32 derivation steps to be taken after the given extended key.
+** Followed by zero or more <tt>/NUM</tt> (may be followed by <tt>h</tt> or <tt>'</tt> to indicate a hardened step) path elements indicating BIP 32 derivation steps to be taken after the given extended key.
-** Optionally followed by a single <tt>/*</tt> (may be followed by <tt>h</tt>, <tt>H</tt>, or <tt>'</tt> to indicate a hardened step) final step to denote all direct unhardened or hardened children.
+** Optionally followed by a single <tt>/*</tt> (may be followed by <tt>h</tt> or <tt>'</tt> to indicate a hardened step) final step to denote all direct unhardened or hardened children.
 
 When a <tt>/<NUM;NUM;...;NUM></tt> is encountered, parsers should account for a presence of multiple descriptors where the first descriptor uses the first <tt>NUM</tt>, and a second descriptor uses the second <tt>NUM</tt>, and so on, until each <tt>NUM</tt> is accounted for in the production of public keys, scripts, and addresses, as well as descriptor import and export operations.
 Descriptors that contain multiple Key Expressions that each have a <tt>/<NUM;NUM;...;NUM></tt> must have tuples of exactly the same length so that they are derived in lockstep in the same way that <tt>/*</tt> paths in multiple Key expressions are handled.
@@ -65,7 +65,7 @@ Valid multipath descriptors followed by the descriptors they expand into as sub-
 * <tt>pkh(xprv9s21ZrQH143K31xYSDQpPDxsXRTUcvj2iNHm5NUtrGiGG5e2DtALGdso3pGz6ssrdK4PFmM8NSpSBHNqPqm55Qn3LqFtT2emdEXVYsCzC2U/<2147483647h;0>/0)</tt>
 ** <tt>pkh(xprv9s21ZrQH143K31xYSDQpPDxsXRTUcvj2iNHm5NUtrGiGG5e2DtALGdso3pGz6ssrdK4PFmM8NSpSBHNqPqm55Qn3LqFtT2emdEXVYsCzC2U/2147483647h/0)</tt>
 ** <tt>pkh(xprv9s21ZrQH143K31xYSDQpPDxsXRTUcvj2iNHm5NUtrGiGG5e2DtALGdso3pGz6ssrdK4PFmM8NSpSBHNqPqm55Qn3LqFtT2emdEXVYsCzC2U/0/0)</tt>
-* <tt>wpkh([ffffffff/13h]xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH/<1;3>/2/*</tt>
+* <tt>wpkh([ffffffff/13h]xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH/<1;3>/2/*)</tt>
 ** <tt>wpkh([ffffffff/13h]xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH/1/2/*)</tt>
 ** <tt>wpkh([ffffffff/13h]xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH/3/2/*)</tt>
 * <tt>multi(2,xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL/<1;2>/*,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/<3;4>/0/*)</tt>

bip-0390.mediawiki

@@ -102,7 +102,7 @@ Invalid descriptors
 * Cannot have multipath participants if <tt>musig()</tt> is also multipath: <tt>tr(musig(xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL/<0;1>,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y)/<2;3>)</tt>
 * <tt>musig()</tt> cannot have hardened derivation steps: <tt>tr(musig(xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y)/0h/*)</tt>
 * <tt>musig()</tt> cannot have hardened child derivation: <tt>tr(musig(xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y)/0/*h)</tt>
-* <tt>musig()</tt> cannot have participants with child derivation when <tt>musig()</tt> has derivation steps: <tt>tr(musig(xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL/*,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/*)/1/2</tt>
+* <tt>musig()</tt> cannot have participants with child derivation when <tt>musig()</tt> has derivation steps: <tt>tr(musig(xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL/*,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/*)/1/2)</tt>
 
 ==Backwards Compatibility==