feat: add Pay-to-Merkle-Root (P2MR) support per BIP 360

README.md

@@ -130,6 +130,8 @@ Some examples interact (via HTTPS) with a 3rd Party Blockchain Provider (3PBP).
 - [Create (and broadcast via 3PBP) a taproot script-path spend Transaction - OP_CHECKSIG](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/taproot.spec.ts)
 - [Create (and broadcast via 3PBP) a taproot script-path spend Transaction - OP_CHECKSEQUENCEVERIFY](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/taproot.spec.ts)
 - [Create (and broadcast via 3PBP) a taproot script-path spend Transaction - OP_CHECKSIGADD (3-of-3)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/taproot.spec.ts)
+- [P2MR (BIP360) address generation and script-path spend](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/p2mr.spec.ts)
+- [P2MR multi-leaf script tree with PSBT signing](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/p2mr.spec.ts)
 - [Generate a random address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.spec.ts)
 - [Import an address via WIF](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.spec.ts)
 - [Generate a 2-of-3 P2SH multisig address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.spec.ts)

src/cjs/address.cjs

@@ -200,6 +200,9 @@ function fromOutputScript(output, network) {
   try {
     return payments.p2tr({ output, network }).address;
   } catch (e) {}
+  try {
+    return payments.p2mr({ output, network }).address;
+  } catch (e) {}
   try {
     return _toFutureSegwitAddress(output, network);
   } catch (e) {}
@@ -239,6 +242,11 @@ function toOutputScript(address, network) {
       } else if (decodeBech32.version === 1) {
         if (decodeBech32.data.length === 32)
           return payments.p2tr({ pubkey: decodeBech32.data }).output;
+      } else if (
+        decodeBech32.version === 2 &&
+        decodeBech32.data.length === 32
+      ) {
+        return payments.p2mr({ hash: decodeBech32.data }).output;
       } else if (
         decodeBech32.version >= FUTURE_SEGWIT_MIN_VERSION &&
         decodeBech32.version <= FUTURE_SEGWIT_MAX_VERSION &&

src/cjs/address.d.ts

@@ -17,11 +17,11 @@ export interface Base58CheckResult {
 }
 /** bech32 decode result */
 export interface Bech32Result {
-    /** address version: 0x00 for P2WPKH、P2WSH, 0x01 for P2TR*/
+    /** address version: 0x00 for P2WPKH/P2WSH, 0x01 for P2TR, 0x02 for P2MR */
     version: number;
-    /** address prefix: bc for P2WPKH、P2WSH、P2TR */
+    /** address prefix: bc for P2WPKH/P2WSH/P2TR/P2MR */
     prefix: string;
-    /** address data：20 bytes for P2WPKH, 32 bytes for P2WSH、P2TR */
+    /** address data：20 bytes for P2WPKH, 32 bytes for P2WSH/P2TR/P2MR */
     data: Uint8Array;
 }
 /**

src/cjs/payments/bip341.cjs

@@ -46,11 +46,13 @@ var __importStar =
 Object.defineProperty(exports, '__esModule', { value: true });
 exports.MAX_TAPTREE_DEPTH = exports.LEAF_VERSION_TAPSCRIPT = void 0;
 exports.rootHashFromPath = rootHashFromPath;
+exports.rootHashFromP2MRPath = rootHashFromP2MRPath;
 exports.toHashTree = toHashTree;
 exports.findScriptPath = findScriptPath;
 exports.tapleafHash = tapleafHash;
 exports.tapTweakHash = tapTweakHash;
 exports.tweakKey = tweakKey;
+exports.tapBranchHash = tapBranchHash;
 const ecc_lib_js_1 = require('../ecc_lib.cjs');
 const bcrypto = __importStar(require('../crypto.cjs'));
 const bufferutils_js_1 = require('../bufferutils.cjs');
@@ -83,6 +85,36 @@ function rootHashFromPath(controlBlock, leafHash) {
   }
   return kj;
 }
+/**
+ * Calculates the root hash from a P2MR control block and leaf hash.
+ * Unlike P2TR, P2MR control blocks do not include an internal public key,
+ * so the Merkle path starts at byte offset 1 (after the control byte).
+ * @param controlBlock - The P2MR control block buffer (1 + 32*m bytes).
+ * @param leafHash - The leaf hash buffer.
+ * @returns The root hash buffer.
+ * @throws {TypeError} If the control block length is invalid.
+ */
+function rootHashFromP2MRPath(controlBlock, leafHash) {
+  if (controlBlock.length < 1)
+    throw new TypeError(
+      `The control-block length is too small. Got ${controlBlock.length}, expected min 1.`,
+    );
+  if ((controlBlock.length - 1) % 32 !== 0)
+    throw new TypeError(
+      `The control-block length of ${controlBlock.length} is incorrect for P2MR!`,
+    );
+  const m = (controlBlock.length - 1) / 32;
+  let kj = leafHash;
+  for (let j = 0; j < m; j++) {
+    const ej = controlBlock.slice(1 + 32 * j, 33 + 32 * j);
+    if (tools.compare(kj, 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.

src/cjs/payments/bip341.d.ts

@@ -28,6 +28,16 @@ export type HashTree = HashLeaf | HashBranch;
  * @throws {TypeError} If the control block length is less than 33.
  */
 export declare function rootHashFromPath(controlBlock: Uint8Array, leafHash: Uint8Array): Uint8Array;
+/**
+ * Calculates the root hash from a P2MR control block and leaf hash.
+ * Unlike P2TR, P2MR control blocks do not include an internal public key,
+ * so the Merkle path starts at byte offset 1 (after the control byte).
+ * @param controlBlock - The P2MR control block buffer (1 + 32*m bytes).
+ * @param leafHash - The leaf hash buffer.
+ * @returns The root hash buffer.
+ * @throws {TypeError} If the control block length is invalid.
+ */
+export declare function rootHashFromP2MRPath(controlBlock: Uint8Array, leafHash: Uint8Array): Uint8Array;
 /**
  * Build a hash tree of merkle nodes from the scripts binary tree.
  * @param scriptTree - the tree of scripts to pairwise hash.
@@ -65,4 +75,12 @@ export declare function tapTweakHash(pubKey: Uint8Array, h: Uint8Array | undefin
  * @returns The tweaked public key or null if the input is invalid.
  */
 export declare function tweakKey(pubKey: Uint8Array, h: Uint8Array | undefined): TweakedPublicKey | null;
+/**
+ * Computes the TapBranch hash by concatenating two buffers and applying the 'TapBranch' tagged hash algorithm.
+ *
+ * @param a - The first buffer.
+ * @param b - The second buffer.
+ * @returns The TapBranch hash of the concatenated buffers.
+ */
+export declare function tapBranchHash(a: Uint8Array, b: Uint8Array): Uint8Array;
 export {};

src/cjs/payments/index.cjs

@@ -1,6 +1,7 @@
 'use strict';
 Object.defineProperty(exports, '__esModule', { value: true });
-exports.p2tr =
+exports.p2mr =
+  exports.p2tr =
   exports.p2wsh =
   exports.p2wpkh =
   exports.p2sh =
@@ -65,5 +66,12 @@ Object.defineProperty(exports, 'p2tr', {
     return p2tr_js_1.p2tr;
   },
 });
+const p2mr_js_1 = require('./p2mr.cjs');
+Object.defineProperty(exports, 'p2mr', {
+  enumerable: true,
+  get: function () {
+    return p2mr_js_1.p2mr;
+  },
+});
 // TODO
 // witness commitment

src/cjs/payments/index.d.ts

@@ -7,6 +7,7 @@
  * - P2WPKH (Pay-to-Witness-PubKey-Hash)
  * - P2WSH (Pay-to-Witness-Script-Hash)
  * - P2TR (Taproot)
+ * - P2MR (Pay-to-Merkle-Root, BIP 360)
  *
  * The `Payment` interface defines the structure of a payment object used for constructing various
  * payment types, with fields for signatures, public keys, redeem scripts, and more.
@@ -23,6 +24,7 @@ import { p2sh } from './p2sh.js';
 import { p2wpkh } from './p2wpkh.js';
 import { p2wsh } from './p2wsh.js';
 import { p2tr } from './p2tr.js';
+import { p2mr } from './p2mr.js';
 export interface Payment {
     name?: string;
     network?: Network;
@@ -52,4 +54,4 @@ export interface PaymentOpts {
 export type StackElement = Uint8Array | number;
 export type Stack = StackElement[];
 export type StackFunction = () => Stack;
-export { embed, p2ms, p2pk, p2pkh, p2sh, p2wpkh, p2wsh, p2tr };
+export { embed, p2ms, p2pk, p2pkh, p2sh, p2wpkh, p2wsh, p2tr, p2mr };