https://github.com/miguelmota/merkletreejs-solidity

Construct merkle trees with MerkleTree.js and verify merkle proofs in Solidity.
https://github.com/miguelmota/merkletreejs-solidity

blockchain ethereum example merkle merkle-hash-trees merkle-proof merkle-root merkle-tree smart-contracts solidity verification

Last synced: about 2 months ago
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Construct merkle trees with MerkleTree.js and verify merkle proofs in Solidity.

• Host: GitHub
• URL: https://github.com/miguelmota/merkletreejs-solidity
• Owner: miguelmota
• License: mit
• Archived: true
• Created: 2018-10-23T06:23:38.000Z (almost 6 years ago)
• Default Branch: master
• Last Pushed: 2022-03-13T08:21:52.000Z (over 2 years ago)
• Last Synced: 2024-07-05T13:54:47.490Z (2 months ago)
• Topics: blockchain, ethereum, example, merkle, merkle-hash-trees, merkle-proof, merkle-root, merkle-tree, smart-contracts, solidity, verification
• Language: JavaScript
• Homepage: https://github.com/miguelmota/merkletreejs-solidity
• Size: 35.2 KB
• Stars: 132
• Watchers: 2
• Forks: 22
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# MerkleTree.js Solidity example

> Construct merkle trees with [MerkleTree.js](https://github.com/miguelmota/merkletreejs) and verify merkle proofs in [Solidity](https://github.com/ethereum/solidity).

## Example

[`contracts/MerkleProof.sol`](./contracts/MerkleProof.sol)

```solidity

pragma solidity ^0.5.2;

contract MerkleProof {

  function verify(

    bytes32 root,

    bytes32 leaf,

    bytes32[] memory proof

  )

    public

    pure

    returns (bool)

  {

    bytes32 computedHash = leaf;

    for (uint256 i = 0; i < proof.length; i++) {

      bytes32 proofElement = proof[i];

      if (computedHash <= proofElement) {

        // Hash(current computed hash + current element of the proof)

        computedHash = keccak256(abi.encodePacked(computedHash, proofElement));

      } else {

        // Hash(current element of the proof + current computed hash)

        computedHash = keccak256(abi.encodePacked(proofElement, computedHash));

      }

    }

    // Check if the computed hash (root) is equal to the provided root

    return computedHash == root;

  }

}

```

[`test/merkleproof.js`](./test/merkleproof.js)

```js

const MerkleProof = artifacts.require('MerkleProof')

const MerkleTree = require('merkletreejs')

const keccak256 = require('keccak256')

const contract = await MerkleProof.new()

const leaves = ['a', 'b', 'c', 'd'].map(v => keccak256(v))

const tree = new MerkleTree(leaves, keccak256, { sort: true })

const root = tree.getHexRoot()

const leaf = keccak256('a')

const proof = tree.getHexProof(leaf)

console.log(await contract.verify.call(root, leaf, proof)) // true

const badLeaves = ['a', 'b', 'x', 'd'].map(v => keccak256(v))

const badTree = new MerkleTree(badLeaves, keccak256, { sort: true })

const badProof = badTree.getHexProof(leaf)

console.log(await contract.verify.call(root, leaf, badProof)) // false

```

## Test

```bash

make test

```

## License

MIT