A hash tree or merkle tree is a tree in which every leaf node is labelled with the hash of a data block and every non-leaf node is labelled with the cryptographic hash of the labels of its child nodes. Merkle trees in Dat are specialized flat trees that contain the content of the archives.

Install

$ pip install merkle-tree-stream

Example

import hashlib

from merkle_tree_stream import MerkleTreeGenerator


def _leaf(node, roots=None):
    return hashlib.sha256(node.data).digest()


def _parent(first, second):
    sha256 = hashlib.sha256()
    sha256.update(first.data)
    sha256.update(second.data)
    return sha256.digest()


merkle = MerkleTreeGenerator(leaf=_leaf, parent=_parent)

merkle.write(b"a")
merkle.write(b"b")

print(merkle._nodes)

Output:

[
 MerkleTreeNode(index=0, parent=1, size=1, data=b'a', hash=b'...'),
 MerkleTreeNode(index=2, parent=1, size=1, data=b'b', hash=b'...'),
 MerkleTreeNode(index=1, parent=3, size=2, data=b'', hash=b'...')
]