Crates a Merkle Tree using the given data, per light Clients for Lazy Blockchains paper by Ertem Nusret Tas et. al

merkle.py

import hashlib
import binascii

def H(data):
    if type(data) == str:
        data = str.encode(data)
    if type(data) == int:
        data = data.to_bytes(4, 'big')
    return hashlib.sha256(data).digest()

class Tree:
    def __init__(self, root, data, left, right):
        self.root = root
        self.data = data
        self.left = left
        self.right = right

def makeMerkleTree(dataList):
    if len(dataList) == 1:
        return Tree(H(dataList[0]), dataList[0], None, None)
    mid = len(dataList)//2
    tree = Tree(None, None, makeMerkleTree(dataList[:mid]), makeMerkleTree(dataList[mid:]))
    tree.root = H(tree.left.root + tree.right.root)
    return tree

def printInOrder(tree):
    if tree.root:
        if tree.left:
            printInOrder(tree.left)
        print("hash:", binascii.hexlify(bytearray(tree.root)))
        print("data:", tree.data)
        if tree.right:
            printInOrder(tree.right)

data = [0,1,2,3,4]
merkleTree = makeMerkleTree(data)
print("data:", data)

print("\ntree root:", binascii.hexlify(bytearray(merkleTree.root)))

print("\ntree:")
printInOrder(merkleTree)