Crate merkle_tree_stream

merkle-tree-stream

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

• Documentation
• Crates.io

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

struct S;
impl HashMethods<DefaultNode> for S {
  fn leaf(&self, leaf: &PartialNode, _roots: &[Rc<DefaultNode>]) -> Vec<u8> {
    let data = leaf.as_ref().unwrap();
    sha256::hash(&data).0.to_vec()
  }

  fn parent(&self, a: &DefaultNode, b: &DefaultNode) -> Vec<u8> {
    let mut buf: Vec<u8> = Vec::with_capacity(a.hash().len() + b.hash().len());
    buf.extend_from_slice(a.hash());
    buf.extend_from_slice(b.hash());
    sha256::hash(&buf).0.to_vec()
  }

  fn node(&self, partial: &PartialNode, hash: Vec<u8>) -> DefaultNode {
    DefaultNode::from_partial(partial, hash)
  }
}

fn main() {
  let roots = Vec::new();
  let mut mts = MerkleTreeStream::new(S, roots);
  let mut nodes: Vec<Rc<DefaultNode>> = 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

License

MIT OR Apache-2.0

Structs

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

Traits

HashMethods	Functions that need to be implemented for MerkleTreeStream.
Node	Functions that need to be implemented for the Data that MerkleTreeStream works with.