lol
This commit is contained in:
Sean Bowe
parent
09940b3402
commit
4ad04e62a1
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@ -2,6 +2,11 @@
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name = "incrementalmerkletree"
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version = "0.1.0"
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authors = ["Sean Bowe <ewillbefull@gmail.com>"]
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edition = "2018"
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[dependencies]
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rand = "0.3"
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# [dependencies]
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# rand = "0.8"
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# typenum = "1.12"
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[dev-dependencies]
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proptest = "0.10"
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799
src/lib.rs
799
src/lib.rs
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@ -1,362 +1,521 @@
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#![feature(rustc_private)]
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extern crate rustc;
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extern crate rand;
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//! # `incrementalmerkletree`
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//!
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//! Incremental Merkle Trees are fixed-depth Merkle trees with two primary
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//! capabilities: appending (assigning a value to the next unused leaf and
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//! advancing the tree) and obtaining the root of the tree. Importantly the tree
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//! structure attempts to store the least amount of information necessary to
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//! continue to function; other information should be pruned eagerly to avoid
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//! waste when the tree state is encoded.
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//!
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//! ## Witnessing
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//!
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//! Merkle trees are typically used to show that a value exists in the tree via
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//! an authentication path. We need an API that allows us to identify the
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//! current leaf as a value we wish to compute authentication paths for even as
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//! the tree continues to be appended to in the future; this is called
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//! maintaining a witness. When we're later uninterested in such a leaf, we can
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//! prune a witness and remove all unnecessary information from the structure as
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//! a consequence.
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//!
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//! ## Checkpoints and Rollbacks
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//!
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//! The structure is not append-only in the strict sense. It is possible to
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//! identify the current state of the tree as a "checkpoint" and to remove older
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//! checkpoints that we're no longer interested in. It should be possible to
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//! roll back to any previous checkpoint.
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mod sha256;
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pub trait TreeHasher {
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type Digest: Clone + PartialEq;
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trait Hashable: Clone + Copy {
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fn combine(&Self, &Self) -> Self;
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fn blank() -> Self;
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fn empty_leaf() -> Self::Digest;
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fn combine(a: &Self::Digest, b: &Self::Digest) -> Self::Digest;
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}
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#[derive(Clone)]
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struct IncrementalMerkleTree<T: Hashable> {
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cursor: Leaf<T>,
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depth: usize
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pub struct Tree<H: TreeHasher> {
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leaves: Vec<H::Digest>,
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current_position: usize,
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witnesses: Vec<(usize, H::Digest)>,
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checkpoints: Vec<usize>,
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depth: usize,
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}
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#[derive(Clone)]
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enum Leaf<T: Hashable> {
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Left{parent: Parent<T>, content: T},
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Right{parent: Parent<T>, left: T, content: T}
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}
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impl<H: TreeHasher> Tree<H> {
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/// Creates a new, empty binary tree of specified depth.
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///
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/// # Panics
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///
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/// Panics if the specified depth is zero.
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pub fn new(depth: usize) -> Self {
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if depth == 0 {
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panic!("invalid depth for incremental merkle tree");
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}
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#[derive(Clone)]
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enum Parent<T: Hashable> {
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Empty,
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Left{parent: Box<Parent<T>>},
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Right{left: T, parent: Box<Parent<T>>}
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}
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impl<T: Hashable> Parent<T> {
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fn ascend<'a, F: FnMut(Option<&'a T>) -> bool>(&'a self, mut cb: F) {
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match *self {
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Parent::Empty => {
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if cb(None) {
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self.ascend(cb);
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}
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},
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Parent::Left{ref parent} => {
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if cb(None) {
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parent.ascend(cb);
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}
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},
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Parent::Right{ref left, ref parent} => {
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if cb(Some(left)) {
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parent.ascend(cb);
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}
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}
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Tree {
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leaves: vec![H::empty_leaf(); 1 << depth],
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current_position: 0,
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witnesses: vec![],
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checkpoints: vec![],
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depth,
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}
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}
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fn advance(self, hash: T) -> Parent<T> {
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match self {
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Parent::Empty => {
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Parent::Right {
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left: hash,
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parent: Box::new(Parent::Empty)
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}
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},
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Parent::Left{parent} => {
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Parent::Right {
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left: hash,
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parent: parent
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}
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},
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Parent::Right{left, parent} => {
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Parent::Left{
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parent: Box::new(parent.advance(T::combine(&left, &hash)))
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}
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}
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}
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}
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}
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impl<T: Hashable> IncrementalMerkleTree<T> {
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fn new(d: usize, initial: T) -> IncrementalMerkleTree<T> {
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assert!(d != 0);
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IncrementalMerkleTree {
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cursor: Leaf::Left{parent: Parent::Empty, content: initial},
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depth: d
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/// Appends a new value to the tree at the next available slot. Returns true
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/// if successful and false if the tree is full.
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pub fn append(&mut self, value: &H::Digest) -> bool {
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if self.current_position == (1 << self.depth) {
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false
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} else {
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self.leaves[self.current_position] = value.clone();
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self.current_position += 1;
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true
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}
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}
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fn completed(&self) -> bool {
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match self.cursor {
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Leaf::Left{..} => false,
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Leaf::Right{ref parent, ..} => {
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let complete = &mut true;
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let depth = &mut (self.depth - 1);
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/// Obtains the current root of this Merkle tree.
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pub fn root(&self) -> H::Digest {
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lazy_root::<H>(self.leaves.clone())
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}
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parent.ascend(|left| {
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if *depth == 0 {
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return false;
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}
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if left.is_none() {
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*complete = false;
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return false;
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}
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*depth -= 1;
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true
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});
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*complete
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}
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/// Marks the current tree state leaf as a value that we're interested in
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/// witnessing. Returns true if successful and false if the tree is empty.
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pub fn witness(&mut self) -> bool {
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if self.current_position == 0 {
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return false;
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} else {
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let value = self.leaves[self.current_position - 1].clone();
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self.witnesses.push((self.current_position - 1, value));
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true
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}
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}
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fn append(self, obj: T) -> IncrementalMerkleTree<T> {
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match self.cursor {
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Leaf::Left{parent, content} => {
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IncrementalMerkleTree {
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cursor: Leaf::Right{
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parent: parent,
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left: content,
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content: obj
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},
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depth: self.depth
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/// Obtains an authentication path to the value specified in the tree.
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/// Returns `None` if there is no available authentication path to the
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/// specified value.
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pub fn authentication_path(&self, value: &H::Digest) -> Option<(usize, Vec<H::Digest>)> {
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self.witnesses
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.iter()
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.find(|witness| witness.1 == *value)
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.map(|&(pos, _)| {
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let mut path = vec![];
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let mut index = pos;
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for bit in 0..self.depth {
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index ^= 1 << bit;
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path.push(lazy_root::<H>(self.leaves[index..][0..(1 << bit)].to_vec()));
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index &= usize::MAX << (bit + 1);
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}
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},
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Leaf::Right{parent, left, content} => {
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IncrementalMerkleTree {
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cursor: Leaf::Left{
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parent: parent.advance(T::combine(&left, &content)),
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content: obj
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},
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depth: self.depth
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}
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}
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}
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(pos, path)
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})
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}
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fn unfilled(&self, mut skip: usize) -> usize {
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let parent = match self.cursor {
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Leaf::Left{ref parent, ..} => {
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if skip == 0 {
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return 0;
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} else {
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skip -= 1;
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parent
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}
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},
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Leaf::Right{ref parent, ..} => {
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parent
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}
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};
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let mut depth = &mut 0;
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parent.ascend(|left| {
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*depth += 1;
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match left {
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Some(_) => {
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return true;
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},
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None => {
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if skip == 0 {
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return false;
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} else {
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skip -= 1;
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return true;
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}
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}
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}
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});
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return *depth;
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}
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fn root(&self) -> T {
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self.root_advanced(Some(T::blank()).iter().cycle())
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}
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fn root_advanced<'a, I: Iterator<Item=&'a T>>(&self, mut it: I) -> T where T: 'a {
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let (parent, mut child) = match self.cursor {
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Leaf::Left{ref parent, ref content} => {
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(parent, T::combine(content, it.next().unwrap()))
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},
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Leaf::Right{ref parent, ref left, ref content} => {
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(parent, T::combine(left, content))
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}
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};
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let mut depth = self.depth - 1;
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/// Marks the specified tree state value as a value we're no longer
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/// interested in maintaining a witness for. Returns true if successful and
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/// false if the value is not a known witness.
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pub fn remove_witness(&mut self, value: &H::Digest) -> bool {
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if let Some((position, _)) = self
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.witnesses
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.iter()
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.enumerate()
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.find(|witness| (witness.1).1 == *value)
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{
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let child = &mut child;
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self.witnesses.remove(position);
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parent.ascend(move |left| {
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if depth == 0 {
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return false;
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}
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match left {
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Some(left) => {
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*child = T::combine(left, &*child);
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},
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None => {
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*child = T::combine(&*child, it.next().unwrap());
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}
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}
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depth = depth - 1;
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true
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});
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true
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} else {
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false
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}
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}
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return child;
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/// Marks the current tree state as a checkpoint if it is not already a
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/// checkpoint.
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pub fn checkpoint(&mut self) {
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self.checkpoints.push(self.current_position);
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}
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/// Rewinds the tree state to the previous checkpoint. This function will
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/// fail and return false if there is no previous checkpoint or in the event
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/// witness data would be destroyed in the process.
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pub fn rewind(&mut self) -> bool {
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if let Some(checkpoint) = self.checkpoints.pop() {
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if self.witnesses.iter().any(|&(pos, _)| pos >= checkpoint) {
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self.checkpoints.push(checkpoint);
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return false;
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}
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self.current_position = checkpoint;
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if checkpoint != (1 << self.depth) {
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self.leaves[checkpoint..].fill(H::empty_leaf());
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}
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true
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} else {
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false
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}
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}
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/// Removes the oldest checkpoint. Returns true if successful and false if
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/// there are no checkpoints.
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pub fn pop_checkpoint(&mut self) -> bool {
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if self.checkpoints.is_empty() {
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false
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} else {
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self.checkpoints.remove(0);
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true
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}
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}
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/// Start a recording of append operations performed on a tree.
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pub fn recording(&self) -> Recording<H> {
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Recording {
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start_position: self.current_position,
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current_position: self.current_position,
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depth: self.depth,
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appends: vec![],
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}
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}
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/// Plays a recording of append operations back. Returns true if successful
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/// and false if the recording is incompatible with the current tree state.
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pub fn play(&mut self, recording: &Recording<H>) -> bool {
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if recording.start_position == self.current_position && self.depth == recording.depth {
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for val in recording.appends.iter() {
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self.append(val);
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}
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true
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} else {
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false
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}
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}
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}
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#[derive(Clone)]
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struct IncrementalWitness<T: Hashable> {
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tree: IncrementalMerkleTree<T>,
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delta: IncrementalDelta<T>
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pub struct Recording<H: TreeHasher> {
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start_position: usize,
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current_position: usize,
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depth: usize,
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appends: Vec<H::Digest>,
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}
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#[derive(Clone)]
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struct IncrementalDelta<T: Hashable> {
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filled: Vec<T>,
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active: Option<IncrementalMerkleTree<T>>
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impl<H: TreeHasher> Recording<H> {
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/// Appends a new value to the tree at the next available slot. Returns true
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/// if successful and false if the tree is full.
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pub fn append(&mut self, value: &H::Digest) -> bool {
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if self.current_position == (1 << self.depth) {
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false
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} else {
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self.appends.push(value.clone());
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self.current_position += 1;
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true
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}
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}
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/// Plays a recording of append operations back. Returns true if successful
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/// and false if the provided recording is incompatible with `Self`.
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pub fn play(&mut self, recording: &Self) -> bool {
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if self.current_position == recording.start_position && self.depth == recording.depth {
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self.appends.extend_from_slice(&recording.appends);
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self.current_position = recording.current_position;
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true
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} else {
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false
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}
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}
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}
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impl<T: Hashable> IncrementalWitness<T> {
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fn new(from: &IncrementalMerkleTree<T>) -> IncrementalWitness<T> {
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IncrementalWitness {
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tree: from.clone(),
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delta: IncrementalDelta {
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filled: vec![],
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active: None
|
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fn lazy_root<H: TreeHasher>(mut leaves: Vec<H::Digest>) -> H::Digest {
|
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while leaves.len() != 1 {
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leaves = leaves
|
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.iter()
|
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.enumerate()
|
||||
.filter(|(i, _)| (i % 2) == 0)
|
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.map(|(_, a)| a)
|
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.zip(
|
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leaves
|
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.iter()
|
||||
.enumerate()
|
||||
.filter(|(i, _)| (i % 2) == 1)
|
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.map(|(_, b)| b),
|
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)
|
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.map(|(a, b)| H::combine(a, b))
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.collect();
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}
|
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|
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leaves[0].clone()
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}
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|
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#[cfg(test)]
|
||||
mod tests {
|
||||
#![allow(deprecated)]
|
||||
use super::*;
|
||||
use std::hash::Hasher;
|
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use std::hash::SipHasher as Hash;
|
||||
|
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impl TreeHasher for Hash {
|
||||
type Digest = u64;
|
||||
|
||||
fn empty_leaf() -> Self::Digest {
|
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0
|
||||
}
|
||||
fn combine(a: &Self::Digest, b: &Self::Digest) -> Self::Digest {
|
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let mut hasher = Hash::new();
|
||||
hasher.write_u64(*a);
|
||||
hasher.write_u64(*b);
|
||||
hasher.finish()
|
||||
}
|
||||
}
|
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|
||||
fn compute_root_from_auth_path<H: TreeHasher>(
|
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value: H::Digest,
|
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position: usize,
|
||||
path: &[H::Digest],
|
||||
) -> H::Digest {
|
||||
let mut cur = value;
|
||||
for (i, v) in path
|
||||
.iter()
|
||||
.enumerate()
|
||||
.map(|(i, v)| (((position >> i) & 1) == 1, v))
|
||||
{
|
||||
if i {
|
||||
cur = H::combine(v, &cur);
|
||||
} else {
|
||||
cur = H::combine(&cur, v);
|
||||
}
|
||||
}
|
||||
cur
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_compute_root_from_auth_path() {
|
||||
let expected = Hash::combine(
|
||||
&Hash::combine(&Hash::combine(&0, &1), &Hash::combine(&2, &3)),
|
||||
&Hash::combine(&Hash::combine(&4, &5), &Hash::combine(&6, &7)),
|
||||
);
|
||||
|
||||
assert_eq!(
|
||||
compute_root_from_auth_path::<Hash>(
|
||||
0,
|
||||
0,
|
||||
&[
|
||||
1,
|
||||
Hash::combine(&2, &3),
|
||||
Hash::combine(&Hash::combine(&4, &5), &Hash::combine(&6, &7))
|
||||
]
|
||||
),
|
||||
expected
|
||||
);
|
||||
|
||||
assert_eq!(
|
||||
compute_root_from_auth_path::<Hash>(
|
||||
4,
|
||||
4,
|
||||
&[
|
||||
5,
|
||||
Hash::combine(&6, &7),
|
||||
Hash::combine(&Hash::combine(&0, &1), &Hash::combine(&2, &3))
|
||||
]
|
||||
),
|
||||
expected
|
||||
);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn correct_empty_root() {
|
||||
const DEPTH: usize = 5;
|
||||
let mut expected = 0u64;
|
||||
for _ in 0..DEPTH {
|
||||
expected = Hash::combine(&expected, &expected);
|
||||
}
|
||||
|
||||
let tree = Tree::<Hash>::new(DEPTH);
|
||||
assert_eq!(tree.root(), expected);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn correct_root() {
|
||||
const DEPTH: usize = 3;
|
||||
let values: Vec<u64> = (0..(1 << DEPTH)).collect();
|
||||
|
||||
let mut tree = Tree::<Hash>::new(DEPTH);
|
||||
for value in values.iter() {
|
||||
assert!(tree.append(value));
|
||||
}
|
||||
assert!(!tree.append(&0));
|
||||
|
||||
let expected = Hash::combine(
|
||||
&Hash::combine(&Hash::combine(&0, &1), &Hash::combine(&2, &3)),
|
||||
&Hash::combine(&Hash::combine(&4, &5), &Hash::combine(&6, &7)),
|
||||
);
|
||||
|
||||
assert_eq!(tree.root(), expected);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn correct_auth_path() {
|
||||
const DEPTH: usize = 3;
|
||||
let values: Vec<u64> = (0..(1 << DEPTH)).collect();
|
||||
|
||||
let mut tree = Tree::<Hash>::new(DEPTH);
|
||||
for value in values.iter() {
|
||||
assert!(tree.append(value));
|
||||
tree.witness();
|
||||
}
|
||||
assert!(!tree.append(&0));
|
||||
|
||||
let expected = Hash::combine(
|
||||
&Hash::combine(&Hash::combine(&0, &1), &Hash::combine(&2, &3)),
|
||||
&Hash::combine(&Hash::combine(&4, &5), &Hash::combine(&6, &7)),
|
||||
);
|
||||
|
||||
assert_eq!(tree.root(), expected);
|
||||
|
||||
for i in 0..(1 << DEPTH) {
|
||||
println!("value: {}", i);
|
||||
let (position, path) = tree.authentication_path(&i).unwrap();
|
||||
assert_eq!(
|
||||
compute_root_from_auth_path::<Hash>(i, position, &path),
|
||||
expected
|
||||
);
|
||||
}
|
||||
}
|
||||
|
||||
use proptest::prelude::*;
|
||||
|
||||
#[derive(Clone, Debug)]
|
||||
enum Operation {
|
||||
Append(u64),
|
||||
Witness,
|
||||
Unwitness(u64),
|
||||
Checkpoint,
|
||||
Rewind,
|
||||
PopCheckpoint,
|
||||
Authpath(u64),
|
||||
}
|
||||
|
||||
use Operation::*;
|
||||
|
||||
prop_compose! {
|
||||
fn arb_operation()
|
||||
(
|
||||
opid in (0..7),
|
||||
item in (0..32u64),
|
||||
)
|
||||
-> Operation
|
||||
{
|
||||
match opid {
|
||||
0 => Append(item),
|
||||
1 => Witness,
|
||||
2 => Unwitness(item),
|
||||
3 => Checkpoint,
|
||||
4 => Rewind,
|
||||
5 => PopCheckpoint,
|
||||
6 => Authpath(item),
|
||||
_ => unimplemented!()
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn append(&mut self, object: T) {
|
||||
match self.delta.active.take() {
|
||||
Some(active) => {
|
||||
let active = active.append(object);
|
||||
proptest! {
|
||||
#[test]
|
||||
fn do_stuff(ops in proptest::collection::vec(arb_operation(), 1..200)) {
|
||||
const DEPTH: usize = 4;
|
||||
let mut tree = Tree::<Hash>::new(DEPTH);
|
||||
let mut tree_size = 0;
|
||||
let mut tree_values = vec![];
|
||||
let mut tree_checkpoints = vec![];
|
||||
let mut tree_witnesses: Vec<(usize, u64)> = vec![];
|
||||
|
||||
if active.completed() {
|
||||
self.delta.filled.push(active.root());
|
||||
} else {
|
||||
self.delta.active = Some(active);
|
||||
}
|
||||
},
|
||||
None => {
|
||||
match self.tree.unfilled(self.delta.filled.len()) {
|
||||
0 => {
|
||||
self.delta.filled.push(object);
|
||||
},
|
||||
i => {
|
||||
self.delta.active = Some(IncrementalMerkleTree::new(i, object));
|
||||
for op in ops {
|
||||
assert_eq!(tree_size, tree_values.len());
|
||||
match op {
|
||||
Append(value) => {
|
||||
if tree.append(&value) {
|
||||
assert!(tree_size < (1 << DEPTH));
|
||||
tree_size += 1;
|
||||
tree_values.push(value);
|
||||
} else {
|
||||
assert!(tree_size == (1 << DEPTH));
|
||||
}
|
||||
}
|
||||
Witness => {
|
||||
if tree.witness() {
|
||||
assert!(tree_size != 0);
|
||||
tree_witnesses.push((tree_size - 1, *tree_values.last().unwrap()));
|
||||
} else {
|
||||
assert!(tree_size == 0);
|
||||
}
|
||||
}
|
||||
Unwitness(value) => {
|
||||
if tree.remove_witness(&value) {
|
||||
if let Some((i, _)) = tree_witnesses.iter().enumerate().find(|v| (v.1).1 == value) {
|
||||
tree_witnesses.remove(i);
|
||||
} else {
|
||||
panic!("witness should not have been removed");
|
||||
}
|
||||
} else {
|
||||
if tree_witnesses.iter().find(|v| v.1 == value).is_some() {
|
||||
panic!("witness should have been removed");
|
||||
}
|
||||
}
|
||||
}
|
||||
Checkpoint => {
|
||||
tree_checkpoints.push(tree_size);
|
||||
tree.checkpoint();
|
||||
}
|
||||
Rewind => {
|
||||
if tree.rewind() {
|
||||
assert!(tree_checkpoints.len() > 0);
|
||||
let checkpoint_location = tree_checkpoints.pop().unwrap();
|
||||
for &(index, _) in tree_witnesses.iter() {
|
||||
// index is the index in tree_values
|
||||
// checkpoint_location is the size of the tree
|
||||
// at the time of the checkpoint
|
||||
// index should always be strictly smaller or
|
||||
// else a witness would be erased!
|
||||
assert!(index < checkpoint_location);
|
||||
}
|
||||
tree_values.truncate(checkpoint_location);
|
||||
tree_size = checkpoint_location;
|
||||
} else {
|
||||
if tree_checkpoints.len() != 0 {
|
||||
let checkpoint_location = *tree_checkpoints.last().unwrap();
|
||||
assert!(tree_witnesses.iter().any(|&(index, _)| index >= checkpoint_location));
|
||||
}
|
||||
}
|
||||
}
|
||||
PopCheckpoint => {
|
||||
if tree.pop_checkpoint() {
|
||||
assert!(tree_checkpoints.len() > 0);
|
||||
tree_checkpoints.remove(0);
|
||||
} else {
|
||||
assert!(tree_checkpoints.len() == 0);
|
||||
}
|
||||
}
|
||||
Authpath(value) => {
|
||||
if let Some((position, path)) = tree.authentication_path(&value) {
|
||||
// must be the case that value was a witness
|
||||
assert!(tree_witnesses.iter().any(|&(_, witness)| witness == value));
|
||||
|
||||
let mut extended_tree_values = tree_values.clone();
|
||||
extended_tree_values.resize(1 << DEPTH, Hash::empty_leaf());
|
||||
let expected_root = lazy_root::<Hash>(extended_tree_values);
|
||||
|
||||
let tree_root = tree.root();
|
||||
assert_eq!(tree_root, expected_root);
|
||||
|
||||
assert_eq!(
|
||||
compute_root_from_auth_path::<Hash>(value, position, &path),
|
||||
expected_root
|
||||
);
|
||||
} else {
|
||||
// must be the case that value wasn't a witness
|
||||
for &(_, witness) in tree_witnesses.iter() {
|
||||
assert!(witness != value);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn root(&self) -> T {
|
||||
self.tree.root_advanced(self.delta.filled.iter() // use filled values
|
||||
.chain(self.delta.active.as_ref().map(|x| x.root()).as_ref()) // then use the active root
|
||||
.chain(Some(T::blank()).iter().cycle())) // then fill in with blanks
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
mod test {
|
||||
use super::{IncrementalMerkleTree, IncrementalWitness};
|
||||
use super::sha256::*;
|
||||
|
||||
#[test]
|
||||
fn test_root() {
|
||||
let a = Sha256Digest::rand(0);
|
||||
|
||||
let tree = IncrementalMerkleTree::new(3, a);
|
||||
|
||||
assert_eq!(tree.root(), Sha256Digest([94, 162, 216, 229, 230, 128, 153, 35, 89, 40, 180, 159, 125, 27, 48, 80, 181, 73, 7, 195, 182, 223, 83, 165, 59, 200, 234, 181, 106, 3, 243, 228]));
|
||||
|
||||
let b = Sha256Digest::rand(1);
|
||||
|
||||
let tree = tree.append(b);
|
||||
|
||||
assert_eq!(tree.root(), Sha256Digest([222, 23, 196, 222, 130, 80, 115, 139, 134, 72, 108, 150, 235, 75, 216, 5, 63, 101, 2, 237, 51, 47, 165, 216, 40, 15, 209, 176, 10, 192, 224, 26]));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_unfilled() {
|
||||
let a = Sha256Digest::rand(0);
|
||||
let mut tree = IncrementalMerkleTree::new(3, a);
|
||||
|
||||
for i in 0..4 {
|
||||
let b = Sha256Digest::rand(i+1);
|
||||
tree = tree.append(b);
|
||||
}
|
||||
|
||||
assert_eq!(tree.unfilled(0), 0);
|
||||
assert_eq!(tree.unfilled(1), 1);
|
||||
assert_eq!(tree.unfilled(2), 3);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_complete() {
|
||||
let a = Sha256Digest::rand(0);
|
||||
let mut tree = IncrementalMerkleTree::new(3, a);
|
||||
|
||||
for i in 0..7 {
|
||||
assert_eq!(tree.completed(), false);
|
||||
let b = Sha256Digest::rand(i+1);
|
||||
tree = tree.append(b);
|
||||
}
|
||||
|
||||
assert_eq!(tree.completed(), true);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_witness() {
|
||||
let a = Sha256Digest::rand(0);
|
||||
let mut tree = IncrementalMerkleTree::new(3, a);
|
||||
|
||||
let mut witness = IncrementalWitness::new(&tree);
|
||||
|
||||
assert_eq!(tree.root(), witness.root());
|
||||
assert_eq!(witness.delta.filled.len(), 0);
|
||||
assert!(witness.delta.active.is_none());
|
||||
|
||||
for i in 1..8 {
|
||||
let b = Sha256Digest::rand(i);
|
||||
witness.append(b);
|
||||
tree = tree.append(b);
|
||||
|
||||
match i {
|
||||
1 => {
|
||||
assert_eq!(witness.delta.filled.len(), 1);
|
||||
assert!(witness.delta.active.is_none());
|
||||
},
|
||||
i if i <= 2 => {
|
||||
assert_eq!(witness.delta.filled.len(), 1);
|
||||
assert!(witness.delta.active.is_some());
|
||||
},
|
||||
i if i == 3 => {
|
||||
assert_eq!(witness.delta.filled.len(), 2);
|
||||
assert!(witness.delta.active.is_none());
|
||||
},
|
||||
i if i < 7 => {
|
||||
assert_eq!(witness.delta.filled.len(), 2);
|
||||
assert!(witness.delta.active.is_some());
|
||||
},
|
||||
a @ _ => {
|
||||
assert_eq!(a, 7);
|
||||
assert_eq!(witness.delta.filled.len(), 3);
|
||||
assert!(witness.delta.active.is_none());
|
||||
}
|
||||
}
|
||||
|
||||
assert_eq!(tree.root(), witness.root());
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -1,68 +0,0 @@
|
|||
use rustc::util::sha2::{Digest,Sha256};
|
||||
use std::u8;
|
||||
|
||||
use super::Hashable;
|
||||
|
||||
impl Hashable for Sha256Digest {
|
||||
fn combine(left: &Self, right: &Self) -> Sha256Digest {
|
||||
sha256_compression_function(Sha256Block::new_from_digests(left, right))
|
||||
}
|
||||
|
||||
fn blank() -> Sha256Digest {
|
||||
Sha256Digest([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
|
||||
}
|
||||
}
|
||||
|
||||
struct Sha256Block(pub [u8; 64]);
|
||||
impl Sha256Block {
|
||||
fn new_from_digests(left: &Sha256Digest, right: &Sha256Digest) -> Sha256Block {
|
||||
use std::mem;
|
||||
|
||||
struct CompoundDigest {
|
||||
left: Sha256Digest,
|
||||
right: Sha256Digest
|
||||
}
|
||||
|
||||
let compound = CompoundDigest { left: *left, right: *right };
|
||||
|
||||
unsafe { mem::transmute(compound) }
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
|
||||
pub struct Sha256Digest(pub [u8; 32]);
|
||||
|
||||
impl Sha256Digest {
|
||||
pub fn rand(seed: usize) -> Sha256Digest {
|
||||
use rand::{self,Rng,SeedableRng,StdRng};
|
||||
|
||||
let seed: [usize; 1] = [seed];
|
||||
|
||||
let mut rng = StdRng::from_seed(&seed);
|
||||
|
||||
Sha256Digest([rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(),
|
||||
rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(),
|
||||
rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(),
|
||||
rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen(), rng.gen()
|
||||
])
|
||||
}
|
||||
}
|
||||
|
||||
// todo: this is not a compression function
|
||||
fn sha256_compression_function(block: Sha256Block) -> Sha256Digest {
|
||||
let mut hash = Sha256::new();
|
||||
|
||||
hash.input(&block.0);
|
||||
|
||||
let res = hash.result_bytes();
|
||||
|
||||
let mut s = Sha256Digest([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]);
|
||||
|
||||
unsafe {
|
||||
use std::ptr;
|
||||
|
||||
ptr::copy_nonoverlapping::<u8>(&res[0], &mut (s.0)[0], 32);
|
||||
}
|
||||
|
||||
s
|
||||
}
|
||||
Loading…
Reference in New Issue