Perkle: A simple Python 3 implementation of Merkle Trees

Perkle provides a simple, all python, implementation of Merkle Trees.

Installation

The package can be installed via pip:

pip install perkle

or by cloning this repository.

The package pycryptodome is in the requirements. Make sure that this will not conflict with an installation of the (deprecated) package pycrypto.

Example

Here is how to create a Merkle Tree of numbers from 0 to 9:

from Crypto.Hash import SHA256
from perkle import MerkleTree
from binascii import hexlify
data_list = [b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9']
sha256 = lambda x : SHA256.new(x).digest() 
mt = MerkleTree(data_list, sha256, random_padding=False, padding_byte=b'0')
print(hexlify(mt.root()))
#70cc27c03c0444d1dfc63f58e373a2882a7b9f4f7f6ed1a4dfc1a94a5ac5875c

By default, we add a random padding to the data to have a power of two leaves. You can make the padding non-random with the random_padding parameter to make the results consistent.

New data can be inserted in the Merkle Tree:

data = b'10'
mt.insert(data)
print(hexlify(mt.root()))
#3e32b51c76de4b124f1fedfbb4d5a30d117274bf04b538ca7f10434e2f8a35b9

And existing data can be updated:

new_data = b'zero'
mt.update(0,new_data)
print(hexlify(mt.root()))
#d485ca0c92d339d2e8495216cdb420f0e215003fffdb62d09da56d8739c94a11

Proofs can be easily generated:

index, proof_hashes = mt.proof(b'7')

and verified:

print(MerkleTree.verify(b'7',index,proof_hashes,mt.root(),sha256))
#True