Merkle Tree Implementation

A TypeScript implementation of a Merkle tree with support for multiple hash algorithms.

Features

• Support for multiple hash algorithms (SHA-1, SHA-256, SHA-512, RIPEMD-160, Whirlpool, MD5)
• Custom hash function support
• TypeScript support with full type definitions
• Comprehensive test coverage
• Serialization and deserialization
• Proof generation and verification

Installation

npm install merkle-tree-ts

Usage

import { MerkleTree } from 'merkle-tree-ts';

// Create a tree with default SHA-256
const tree = new MerkleTree(['a', 'b', 'c', 'd']);

// Create a tree with a specific hash algorithm
const tree = new MerkleTree(['a', 'b', 'c', 'd'], { 
  hashAlgorithm: 'sha512' 
});

// Create a tree with a custom hash function
const customHash = (data: Buffer) => Buffer.from('custom');
const tree = new MerkleTree(['a', 'b', 'c', 'd'], { 
  hashFunction: customHash 
});

// Get the root hash
const root = tree.root;

// Generate a proof for a leaf
const proof = tree.getProof(0);

// Verify a proof
const isValid = tree.verify(proof, 'a', root);

// Serialize the tree
const serialized = tree.toJSON();

// Deserialize the tree
const deserialized = MerkleTree.fromJSON(serialized);

Supported Hash Algorithms

• SHA-1
• SHA-256 (default)
• SHA-512
• RIPEMD-160
• Whirlpool
• MD5

API

Constructor

new MerkleTree(leaves: (Buffer | string)[], options?: MerkleTreeOptions)

Options

interface MerkleTreeOptions {
  hashAlgorithm?: HashAlgorithm;  // One of: 'sha1', 'sha256', 'sha512', 'ripemd160', 'whirlpool', 'md5'
  hashFunction?: HashFunction;    // Custom hash function: (data: Buffer) => Buffer
}

Methods

• getRoot(): Buffer - Get the root hash
• getProof(index: number): MerkleProof - Generate a proof for a leaf
• verify(proof: MerkleProof, leaf: Buffer | string, root: Buffer): boolean - Verify a proof
• toJSON(): string - Serialize the tree
• static fromJSON(json: string): MerkleTree - Deserialize the tree

Types

type HashAlgorithm = 'sha1' | 'sha256' | 'sha512' | 'ripemd160' | 'whirlpool' | 'md5';

type HashFunction = (data: Buffer) => Buffer;

interface MerkleProof {
  siblings: Buffer[];
  path: number[];
}

interface MerkleTreeOptions {
  hashAlgorithm?: HashAlgorithm;
  hashFunction?: HashFunction;
}

Error Handling

The library throws MerkleTreeError for various error conditions:

• Empty leaves array
• Invalid hash algorithm
• Invalid hash function
• Invalid proof
• Invalid serialized data

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT