Hi Andrew,
I'm confused why PSBT_IN_TAP_BIP32_DERIVATION and PSBT_OUT_TAP_BIP32_DERIVATION
contain not just the derivation path for the xonlypubkey, but also the tapleaf merkle path.
First I thought it was perhaps necessary in order for a signer to guess which
script leaves it can sign with its own keys. But you can't really know that without
actually seeing the script. When a signer looks at a script, it presumably already
knows the leaf path.
- Sjors
Hi All,
I would like to propose a BIP which defines new fields for Taproot
support in PSBT.
The full text is below, and the rendered file can be found at
-
| Taproot Key BIP 32 Derivation Path
| <tt>PSBT_IN_TAP_BIP32_DERIVATION = 0x16</tt>
| <tt><xonlypubkey></tt>
| The 32 byte X-only public key
| <tt><hashes len> <leaf hash>* <32-bit uint> <32-bit uint>*</tt>
| A compact size unsigned integer representing the number of leaf
hashes, followed by a list of leaf hashes, followed by the master key
fingerprint concatenated with the derivation path of the public key. The
derivation path is represented as 32-bit little endian unsigned integer
indexes concatenated with each other. Public keys are those needed to
spend this output. The leaf hashes are of the leaves which involve this
public key.
|-
| Taproot Key BIP 32 Derivation Path
| <tt>PSBT_OUT_TAP_BIP32_DERIVATION = 0x07</tt>
| <tt><xonlypubkey></tt>
| The 32 byte X-only public key
| <tt><hashes len> <leaf hash>* <32-bit uint> <32-bit uint>*</tt>