feat(p2tr): expose internalPubkey

required for verifying PSBT outputs

Issue: BG-54756

Author: reardencode

src/payments/index.d.ts

@@ -22,6 +22,7 @@ export interface Payment {
     input?: Buffer;
     signatures?: Buffer[];
     pubkey?: Buffer;
+    internalPubkey?: Buffer;
     signature?: Buffer;
     address?: string;
     hash?: Buffer;

src/payments/p2tr.js

@@ -103,15 +103,15 @@ function p2tr(a, opts) {
     if (parsedWitness && parsedWitness.spendType === 'Script')
       return taproot.parseControlBlock(ecc, parsedWitness.controlBlock);
   });
-  const _internalPubkey = lazy.value(() => {
+  lazy.prop(o, 'internalPubkey', () => {
     if (a.pubkey) {
       // single pubkey
       return a.pubkey;
     } else if (a.pubkeys && a.pubkeys.length === 1) {
       return a.pubkeys[0];
     } else if (a.pubkeys && a.pubkeys.length > 1) {
       // multiple pubkeys
-      return taproot.aggregateMuSigPubkeys(ecc, a.pubkeys);
+      return Buffer.from(taproot.aggregateMuSigPubkeys(ecc, a.pubkeys));
     } else if (_parsedControlBlock()) {
       return _parsedControlBlock().internalPubkey;
     } else {
@@ -153,7 +153,7 @@ function p2tr(a, opts) {
         );
     }
     if (!taptreeRoot && _taprootPaths()) taptreeRoot = _taprootPaths().root;
-    return taproot.tapTweakPubkey(ecc, _internalPubkey(), taptreeRoot);
+    return taproot.tapTweakPubkey(ecc, o.internalPubkey, taptreeRoot);
   });
   lazy.prop(o, 'tapTree', () => {
     if (!a.redeems) return;
@@ -192,7 +192,7 @@ function p2tr(a, opts) {
     if (!taprootPaths || !taprootPubkey || a.redeemIndex === undefined) return;
     return taproot.getControlBlock(
       taprootPubkey.parity,
-      _internalPubkey(),
+      o.internalPubkey,
       taprootPaths.paths[a.redeemIndex],
     );
   });
@@ -289,7 +289,7 @@ function p2tr(a, opts) {
         throw new TypeError('mismatch between address and taproot pubkey');
     const parsedControlBlock = _parsedControlBlock();
     if (parsedControlBlock) {
-      if (!parsedControlBlock.internalPubkey.equals(_internalPubkey()))
+      if (!parsedControlBlock.internalPubkey.equals(o.internalPubkey))
         throw new TypeError('Internal pubkey mismatch');
       if (taprootPubkey && parsedControlBlock.parity !== taprootPubkey.parity)
         throw new TypeError('Parity mismatch');

ts_src/payments/index.ts

@@ -22,6 +22,7 @@ export interface Payment {
   input?: Buffer;
   signatures?: Buffer[];
   pubkey?: Buffer;
+  internalPubkey?: Buffer;
   signature?: Buffer;
   address?: string;
   hash?: Buffer;

ts_src/payments/p2tr.ts

@@ -117,15 +117,16 @@ export function p2tr(a: Payment, opts?: PaymentOpts): Payment {
     if (parsedWitness && parsedWitness.spendType === 'Script')
       return taproot.parseControlBlock(ecc, parsedWitness.controlBlock);
   });
-  const _internalPubkey = lazy.value(() => {
+
+  lazy.prop(o, 'internalPubkey', () => {
     if (a.pubkey) {
       // single pubkey
       return a.pubkey;
     } else if (a.pubkeys && a.pubkeys.length === 1) {
       return a.pubkeys[0];
     } else if (a.pubkeys && a.pubkeys.length > 1) {
       // multiple pubkeys
-      return taproot.aggregateMuSigPubkeys(ecc, a.pubkeys);
+      return Buffer.from(taproot.aggregateMuSigPubkeys(ecc, a.pubkeys));
     } else if (_parsedControlBlock()) {
       return _parsedControlBlock()!.internalPubkey;
     } else {
@@ -169,7 +170,7 @@ export function p2tr(a: Payment, opts?: PaymentOpts): Payment {
     }
     if (!taptreeRoot && _taprootPaths()) taptreeRoot = _taprootPaths()!.root;
 
-    return taproot.tapTweakPubkey(ecc, _internalPubkey(), taptreeRoot);
+    return taproot.tapTweakPubkey(ecc, o.internalPubkey!, taptreeRoot);
   });
 
   lazy.prop(o, 'tapTree', () => {
@@ -209,7 +210,7 @@ export function p2tr(a: Payment, opts?: PaymentOpts): Payment {
     if (!taprootPaths || !taprootPubkey || a.redeemIndex === undefined) return;
     return taproot.getControlBlock(
       taprootPubkey.parity,
-      _internalPubkey(),
+      o.internalPubkey!,
       taprootPaths.paths[a.redeemIndex],
     );
   });
@@ -319,7 +320,7 @@ export function p2tr(a: Payment, opts?: PaymentOpts): Payment {
 
     const parsedControlBlock = _parsedControlBlock();
     if (parsedControlBlock) {
-      if (!parsedControlBlock.internalPubkey.equals(_internalPubkey()))
+      if (!parsedControlBlock.internalPubkey.equals(o.internalPubkey!))
         throw new TypeError('Internal pubkey mismatch');
       if (taprootPubkey && parsedControlBlock.parity !== taprootPubkey.parity)
         throw new TypeError('Parity mismatch');