vmatekole / merkletree

Merkle tree data structure in pure Javascript

merlketree

Merkle tree data structure in pure Javascript. Always builds complete binary trees.

The proofs are compatible with the chainpoint proof format.

Browser demo

Install

npm install --save merkletree

Usage

import merkletree, { verifyProof } from 'merkletree'

/* with require:
const mtree = require('merkletree')
const merkletree = mtree.default
const verifyProof = mtree.verifyProof
*/

const leaves = [
  'e1566f09e0deea437826514431be6e4bdb4fe10aa54d75aecf0b4cdc1bc4320c',
  '2f7f9092b2d6c5c17cfe2bcf33fc38a41f2e4d4485b198c2b1074bba067e7168',
  'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855',
  'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855',
]
const tree = merkletree(leaves)
console.log(tree.root())
/*
6a9a3c86d47f1fe12648c86368ecd9723ff12e3fc34f6ae219d4d9d3e0d60667
*/
const proof = tree.proof('2f7f9092b2d6c5c17cfe2bcf33fc38a41f2e4d4485b198c2b1074bba067e7168')
console.log(proof)

/*
[
  {
    left: 'e1566f09e0deea437826514431be6e4bdb4fe10aa54d75aecf0b4cdc1bc4320c',
    parent: '0fdd6b6895e15115c262f6acb9a6ae0c73248568b740454ab21591f8a533dd7f',
    right: '2f7f9092b2d6c5c17cfe2bcf33fc38a41f2e4d4485b198c2b1074bba067e7168',
  },
  {
    left: '0fdd6b6895e15115c262f6acb9a6ae0c73248568b740454ab21591f8a533dd7f',
    parent: '6a9a3c86d47f1fe12648c86368ecd9723ff12e3fc34f6ae219d4d9d3e0d60667',
    right: '3b7546ed79e3e5a7907381b093c5a182cbf364c5dd0443dfa956c8cca271cc33',
  },
])
*/
const verified = verifyProof(
  '2f7f9092b2d6c5c17cfe2bcf33fc38a41f2e4d4485b198c2b1074bba067e7168', // leaf
  '6a9a3c86d47f1fe12648c86368ecd9723ff12e3fc34f6ae219d4d9d3e0d60667', // expected merkle root
  proof
)
console.log(verified)
/*
true
*/

TOTO

• memoize hash() calls in tree to speed up branch/root computation