@energyweb/greenproof-merkle-tree v2.0.6

Green Proof Merkle Tree

This package is a wrapper around merkletreejs and can be used to create unified merkle trees.

Installation

1. yarn add @energyweb/greenproof-merkle-tree

Usage

1. Create leaves using exported hash function.
   • Pass string to hash as first argument and key as second argument.
2. Use createMerkleTree function to create merkle tree from leaves.
3. Returned function verify can be used to verify if leaf is present in the constructed tree. Tree is the constructed instance of MerkleTree from merkletreejs library.

Full example:

import {createMerkleTree, hash} from '@energyweb/greenproof-merkle-tree';

const leavesForMerkleTree = [
    hash('my data'),
    hash(JSON.stringify({someData: 1, otherData: '123'})),
];

const {tree, verify} = createMerkleTree(leavesForMerkleTree);

verify(hash('my data')) // `true` -> leaf is present in merkle tree'
verify(JSON.stringify({someData: 1, otherData: '123'})) // `true` -> leaf is in merkle tree

verify(hash('not existing data')) // `false` -> leaf is not in merkle tree
verify(JSON.stringify({someData: 1})) // `false` -> leaf is not in merkle tree

NOTE: key is used to differentiate between leaves with the same values. For example you can have leaves:

const johnFromPoland = hash('John', 'PL');
const johnFromUSA = hash('John', 'USA');

const {verify} = createMerkleTree([johnFromPoland, johnFromUSA]);

verify(johnFromPoland) // true
verify(johnFromUSA) // true
verify(hash('John', 'DE')) // false, as there was no John with such a key in the tree

Refer to unit tests for more examples.