Crate merkle_tree_stream

A stream that generates a merkle tree based on incoming data. Adapted from mafintosh/merkle-tree-stream.

Why?

Signatures & integrity checks are part of what makes Dat a great protocol. Each chunk that passes through the system is hashed and made part of a tree of hashes. We end up creating hashes of hashes thanks to flat-tree, which in the end allows us to validate our complete data set.

This module is only needed to create new Dat archives, but not to read them.

Usage

extern crate merkle_tree_stream;
extern crate rust_sodium;

use merkle_tree_stream::{MerkleTreeStream, Node, PartialNode, HashMethods};
use rust_sodium::crypto::hash::sha256;
use std::rc::Rc;

struct S;
impl HashMethods for S {
  fn leaf(&self, leaf: &PartialNode, _roots: &Vec<Rc<Node>>) -> Vec<u8> {
    match leaf.data {
      Some(ref data) => sha256::hash(&data).0.to_vec(),
      None => panic!("Merkle tree stream did not have any data on the node. This should never happen."),
    }
  }

  fn parent(&self, a: &Node, b: &Node) -> Vec<u8> {
    let mut buffer: Vec<u8> = Vec::with_capacity(a.hash.len() + b.hash.len());
    for c in &a.hash {
      buffer.push(*c);
    }
    for c in &b.hash {
      buffer.push(*c);
    }
    let digest = sha256::hash(&buffer);
    digest.0.to_vec()
  }
}

fn main() {
  let roots = Vec::new();
  let mut mts = MerkleTreeStream::new(S, roots);
  let mut nodes: Vec<Rc<Node>> = Vec::new();
  mts.next(b"hello", &mut nodes);
  mts.next(b"hashed", &mut nodes);
  mts.next(b"world", &mut nodes);
  println!("nodes {:?}", nodes);
}

Installation

$ cargo add merkle-tree-stream

See Also

• flat-tree

Structs

MerkleTreeStream	Main constructor. Takes an instance of HashMethods.
Node	Node representation.
PartialNode	Intermediate Node representation. Same as Node, but without the .hash field.

Traits

HashMethods

Functions that need to be implemented for MerkleTreeStream.

Type Definitions

NodeVector

A vector of Node instances.