merkletree

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