refactor: move tweakKey() to taproot utils

Author: motorina0

src/payments/p2tr.js

@@ -127,7 +127,7 @@ function p2tr(a, opts) {
     if (a.output) return a.output.slice(2);
     if (a.address) return _address().data;
     if (o.internalPubkey) {
-      const tweakedKey = tweakKey(o.internalPubkey, o.hash);
+      const tweakedKey = (0, taprootutils_1.tweakKey)(o.internalPubkey, o.hash);
       if (tweakedKey) return tweakedKey.x;
     }
   });
@@ -152,7 +152,10 @@ function p2tr(a, opts) {
       });
       const path = (0, taprootutils_1.findScriptPath)(hashTree, leafHash);
       if (!path) return;
-      const outputKey = tweakKey(a.internalPubkey, hashTree.hash);
+      const outputKey = (0, taprootutils_1.tweakKey)(
+        a.internalPubkey,
+        hashTree.hash,
+      );
       if (!outputKey) return;
       const controlBock = buffer_1.Buffer.concat(
         [
@@ -193,7 +196,7 @@ function p2tr(a, opts) {
       else pubkey = a.output.slice(2);
     }
     if (a.internalPubkey) {
-      const tweakedKey = tweakKey(a.internalPubkey, o.hash);
+      const tweakedKey = (0, taprootutils_1.tweakKey)(a.internalPubkey, o.hash);
       if (pubkey.length > 0 && !pubkey.equals(tweakedKey.x))
         throw new TypeError('Pubkey mismatch');
       else pubkey = tweakedKey.x;
@@ -274,7 +277,7 @@ function p2tr(a, opts) {
           controlBlock,
           leafHash,
         );
-        const outputKey = tweakKey(internalPubkey, hash);
+        const outputKey = (0, taprootutils_1.tweakKey)(internalPubkey, hash);
         if (!outputKey)
           // todo: needs test data
           throw new TypeError('Invalid outputKey for p2tr witness');
@@ -288,18 +291,6 @@ function p2tr(a, opts) {
   return Object.assign(o, a);
 }
 exports.p2tr = p2tr;
-function tweakKey(pubKey, h) {
-  if (!buffer_1.Buffer.isBuffer(pubKey)) return null;
-  if (pubKey.length !== 32) return null;
-  if (h && h.length !== 32) return null;
-  const tweakHash = (0, taprootutils_1.tapTweakHash)(pubKey, h);
-  const res = (0, ecc_lib_1.getEccLib)().xOnlyPointAddTweak(pubKey, tweakHash);
-  if (!res || res.xOnlyPubkey === null) return null;
-  return {
-    parity: res.parity,
-    x: buffer_1.Buffer.from(res.xOnlyPubkey),
-  };
-}
 function stacksEqual(a, b) {
   if (a.length !== b.length) return false;
   return a.every((x, i) => {

src/payments/taprootutils.d.ts

@@ -1,7 +1,6 @@
 /// <reference types="node" />
 import { Tapleaf, Taptree } from '../types';
 export declare const LEAF_VERSION_TAPSCRIPT = 192;
-export declare function rootHashFromPath(controlBlock: Buffer, leafHash: Buffer): Buffer;
 interface HashLeaf {
     hash: Buffer;
 }
@@ -10,13 +9,18 @@ interface HashBranch {
     left: HashTree;
     right: HashTree;
 }
+interface TweakedPublicKey {
+    parity: number;
+    x: Buffer;
+}
 /**
  * Binary tree representing leaf, branch, and root node hashes of a Taptree.
  * Each node contains a hash, and potentially left and right branch hashes.
  * This tree is used for 2 purposes: Providing the root hash for tweaking,
  * and calculating merkle inclusion proofs when constructing a control block.
  */
 export declare type HashTree = HashLeaf | HashBranch;
+export declare function rootHashFromPath(controlBlock: Buffer, leafHash: Buffer): Buffer;
 /**
  * Build a hash tree of merkle nodes from the scripts binary tree.
  * @param scriptTree - the tree of scripts to pairwise hash.
@@ -33,4 +37,5 @@ export declare function toHashTree(scriptTree: Taptree): HashTree;
 export declare function findScriptPath(node: HashTree, hash: Buffer): Buffer[] | undefined;
 export declare function tapleafHash(leaf: Tapleaf): Buffer;
 export declare function tapTweakHash(pubKey: Buffer, h: Buffer | undefined): Buffer;
+export declare function tweakKey(pubKey: Buffer, h: Buffer | undefined): TweakedPublicKey | null;
 export {};

src/payments/taprootutils.js

@@ -1,11 +1,13 @@
 'use strict';
 Object.defineProperty(exports, '__esModule', { value: true });
-exports.tapTweakHash = exports.tapleafHash = exports.findScriptPath = exports.toHashTree = exports.rootHashFromPath = exports.LEAF_VERSION_TAPSCRIPT = void 0;
+exports.tweakKey = exports.tapTweakHash = exports.tapleafHash = exports.findScriptPath = exports.toHashTree = exports.rootHashFromPath = exports.LEAF_VERSION_TAPSCRIPT = void 0;
 const buffer_1 = require('buffer');
+const ecc_lib_1 = require('../ecc_lib');
 const bcrypto = require('../crypto');
 const bufferutils_1 = require('../bufferutils');
 const types_1 = require('../types');
 exports.LEAF_VERSION_TAPSCRIPT = 0xc0;
+const isHashBranch = ht => 'left' in ht && 'right' in ht;
 function rootHashFromPath(controlBlock, leafHash) {
   const m = (controlBlock.length - 33) / 32;
   let kj = leafHash;
@@ -20,7 +22,6 @@ function rootHashFromPath(controlBlock, leafHash) {
   return kj;
 }
 exports.rootHashFromPath = rootHashFromPath;
-const isHashBranch = ht => 'left' in ht && 'right' in ht;
 /**
  * Build a hash tree of merkle nodes from the scripts binary tree.
  * @param scriptTree - the tree of scripts to pairwise hash.
@@ -76,6 +77,19 @@ function tapTweakHash(pubKey, h) {
   );
 }
 exports.tapTweakHash = tapTweakHash;
+function tweakKey(pubKey, h) {
+  if (!buffer_1.Buffer.isBuffer(pubKey)) return null;
+  if (pubKey.length !== 32) return null;
+  if (h && h.length !== 32) return null;
+  const tweakHash = tapTweakHash(pubKey, h);
+  const res = (0, ecc_lib_1.getEccLib)().xOnlyPointAddTweak(pubKey, tweakHash);
+  if (!res || res.xOnlyPubkey === null) return null;
+  return {
+    parity: res.parity,
+    x: buffer_1.Buffer.from(res.xOnlyPubkey),
+  };
+}
+exports.tweakKey = tweakKey;
 function tapBranchHash(a, b) {
   return bcrypto.taggedHash('TapBranch', buffer_1.Buffer.concat([a, b]));
 }

ts_src/payments/p2tr.ts

@@ -8,7 +8,7 @@ import {
   rootHashFromPath,
   findScriptPath,
   tapleafHash,
-  tapTweakHash,
+  tweakKey,
   LEAF_VERSION_TAPSCRIPT,
 } from './taprootutils';
 import { Payment, PaymentOpts } from './index';
@@ -316,30 +316,6 @@ export function p2tr(a: Payment, opts?: PaymentOpts): Payment {
   return Object.assign(o, a);
 }
 
-interface TweakedPublicKey {
-  parity: number;
-  x: Buffer;
-}
-
-function tweakKey(
-  pubKey: Buffer,
-  h: Buffer | undefined,
-): TweakedPublicKey | null {
-  if (!NBuffer.isBuffer(pubKey)) return null;
-  if (pubKey.length !== 32) return null;
-  if (h && h.length !== 32) return null;
-
-  const tweakHash = tapTweakHash(pubKey, h);
-
-  const res = getEccLib().xOnlyPointAddTweak(pubKey, tweakHash);
-  if (!res || res.xOnlyPubkey === null) return null;
-
-  return {
-    parity: res.parity,
-    x: NBuffer.from(res.xOnlyPubkey),
-  };
-}
-
 function stacksEqual(a: Buffer[], b: Buffer[]): boolean {
   if (a.length !== b.length) return false;
 

ts_src/payments/taprootutils.ts

@@ -1,30 +1,12 @@
 import { Buffer as NBuffer } from 'buffer';
+import { getEccLib } from '../ecc_lib';
 import * as bcrypto from '../crypto';
 
 import { varuint } from '../bufferutils';
 import { Tapleaf, Taptree, isTapleaf } from '../types';
 
 export const LEAF_VERSION_TAPSCRIPT = 0xc0;
 
-export function rootHashFromPath(
-  controlBlock: Buffer,
-  leafHash: Buffer,
-): Buffer {
-  const m = (controlBlock.length - 33) / 32;
-
-  let kj = leafHash;
-  for (let j = 0; j < m; j++) {
-    const ej = controlBlock.slice(33 + 32 * j, 65 + 32 * j);
-    if (kj.compare(ej) < 0) {
-      kj = tapBranchHash(kj, ej);
-    } else {
-      kj = tapBranchHash(ej, kj);
-    }
-  }
-
-  return kj;
-}
-
 interface HashLeaf {
   hash: Buffer;
 }
@@ -35,6 +17,11 @@ interface HashBranch {
   right: HashTree;
 }
 
+interface TweakedPublicKey {
+  parity: number;
+  x: Buffer;
+}
+
 const isHashBranch = (ht: HashTree): ht is HashBranch =>
   'left' in ht && 'right' in ht;
 
@@ -46,6 +33,25 @@ const isHashBranch = (ht: HashTree): ht is HashBranch =>
  */
 export type HashTree = HashLeaf | HashBranch;
 
+export function rootHashFromPath(
+  controlBlock: Buffer,
+  leafHash: Buffer,
+): Buffer {
+  const m = (controlBlock.length - 33) / 32;
+
+  let kj = leafHash;
+  for (let j = 0; j < m; j++) {
+    const ej = controlBlock.slice(33 + 32 * j, 65 + 32 * j);
+    if (kj.compare(ej) < 0) {
+      kj = tapBranchHash(kj, ej);
+    } else {
+      kj = tapBranchHash(ej, kj);
+    }
+  }
+
+  return kj;
+}
+
 /**
  * Build a hash tree of merkle nodes from the scripts binary tree.
  * @param scriptTree - the tree of scripts to pairwise hash.
@@ -104,6 +110,25 @@ export function tapTweakHash(pubKey: Buffer, h: Buffer | undefined): Buffer {
   );
 }
 
+export function tweakKey(
+  pubKey: Buffer,
+  h: Buffer | undefined,
+): TweakedPublicKey | null {
+  if (!NBuffer.isBuffer(pubKey)) return null;
+  if (pubKey.length !== 32) return null;
+  if (h && h.length !== 32) return null;
+
+  const tweakHash = tapTweakHash(pubKey, h);
+
+  const res = getEccLib().xOnlyPointAddTweak(pubKey, tweakHash);
+  if (!res || res.xOnlyPubkey === null) return null;
+
+  return {
+    parity: res.parity,
+    x: NBuffer.from(res.xOnlyPubkey),
+  };
+}
+
 function tapBranchHash(a: Buffer, b: Buffer): Buffer {
   return bcrypto.taggedHash('TapBranch', NBuffer.concat([a, b]));
 }