Fibonacci List + Merkle Tree

fibonacci_merkle.js

const crypto = require('crypto');

// Generate the SHA256 from an input
const SHA256 = (input) => (
  crypto
  .createHash('sha256')
  .update(input)
  .digest()
  .toString('hex')
);

// Double hash for each input in the merkle tree
const SHA256x2 = (val, hashFunc = SHA256) => (
  hashFunc(hashFunc(val))
);

// Generate the merkle tree according to bitcoin protocol
const merklelize = (list) => {
  if (list.length === 1) {
    return SHA256x2(list[0])
  }

  let hashedConcatList = [];
  for (let i = 0; i < list.length; i += 2) {
    let a = list[i];
    let b;

    if (i + 1 >= list.length)
      b = list[i];
    else
      b = list[i + 1];

    let concat = SHA256x2(`${a}`) + SHA256x2(`${b}`);
    hashedConcatList.push(concat);
  }

  return merklelize(hashedConcatList);
};

// Just a fibonacci array
const fibonacciList = (size) => {
  const fib = [0, 1];

  for (let i = fib.length; fib.length < size; i++)
    fib.push(fib[i - 1] + fib[i - 2]);

  return fib;
}

// Generate a fibonacci array with 50 positions
const fibList = fibonacciList(50);

// Return the root of the merkle tree
console.log(merklelize(fibList).toString());