pyth-crosschain/target_chains/sui/contracts/sources/merkle_tree.move

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// Implementation of a Merkle tree in Move. Supports constructing a new tree
// with a given depth, as well as proving that a leaf node belongs to the tree.
module pyth::merkle_tree {
use std::vector::{Self};
use sui::hash::{keccak256};
use wormhole::bytes20::{Self, Bytes20, data};
use wormhole::cursor::Cursor;
use pyth::deserialize::{Self};
#[test_only]
use wormhole::cursor::{Self};
const MERKLE_LEAF_PREFIX: u8 = 0;
const MERKLE_NODE_PREFIX: u8 = 1;
const MERKLE_EMPTY_LEAF_PREFIX: u8 = 2;
const E_DEPTH_NOT_LARGE_ENOUGH_FOR_MESSAGES: u64 = 1212121;
// take keccak256 of input data, then return 20 leftmost bytes of result
fun hash(bytes: &vector<u8>): Bytes20 {
let hashed_bytes = keccak256(bytes);
let hash_prefix = vector::empty<u8>();
let i = 0;
while (i < 20) {
vector::push_back(&mut hash_prefix, *vector::borrow(&hashed_bytes, i));
i = i + 1;
};
bytes20::new(hash_prefix)
}
fun empty_leaf_hash(): Bytes20 {
let v = vector<u8>[MERKLE_EMPTY_LEAF_PREFIX];
hash(&v)
}
fun leaf_hash(data: &vector<u8>): Bytes20 {
let v = vector<u8>[MERKLE_LEAF_PREFIX];
let i = 0;
while (i < vector::length(data)) {
vector::push_back(&mut v, *vector::borrow(data, i));
i = i + 1;
};
hash(&v)
}
fun node_hash(
childA: Bytes20,
childB: Bytes20
): Bytes20 {
if (greater_than(&childA, &childB)) {
(childA, childB) = (childB, childA);
};
// append data_B to data_A
let data_A = bytes20::data(&childA);
let data_B = bytes20::data(&childB);
// create a vector containing MERKLE_NODE_PREFIX + data_A + data_B
let v = vector<u8>[MERKLE_NODE_PREFIX];
let i = 0;
while (i < 20) {
vector::push_back(&mut v, *vector::borrow(&data_A, i));
i = i + 1;
};
let i = 0;
while (i < 20) {
vector::push_back(&mut v, *vector::borrow(&data_B, i));
i = i + 1;
};
hash(&v)
}
// greater_than returns whether a is strictly greater than b
// note that data(&a) and data(&b) are both vector<u8>s of length 20
fun greater_than(a: &Bytes20, b: &Bytes20): bool {
// aa and bb both have length 20
let a_vector = data(a);
let b_vector = data(b);
let i = 0;
while (i < 20) {
let a_value = *vector::borrow(&a_vector, i);
let b_value = *vector::borrow(&b_vector, i);
if (a_value > b_value) {
return true
} else if (b_value > a_value) {
return false
};
i = i + 1;
};
false
}
// The Sui Move stdlb insert function shifts v[i] and subsequent elements to the right.
// We don't want this behavior, so we define our own set_element function that instead replaces the ith element.
// Reference: https://github.com/MystenLabs/sui/blob/main/crates/sui-framework/packages/move-stdlib/sources/vector.move
fun set_element<T: drop>(a: &mut vector<T>, value: T, index: u64){
vector::push_back<T>(a, value); // push value to end
vector::swap_remove(a, index); // swap value to correct position and pop last value
}
// is_proof_valid returns whether a merkle proof is valid
public fun is_proof_valid(
encoded_proof: &mut Cursor<u8>,
root: Bytes20,
leaf_data: vector<u8>,
): bool {
let current_digest: Bytes20 = leaf_hash(&leaf_data);
let proofSize: u8 = deserialize::deserialize_u8(encoded_proof);
while (proofSize > 0){
let sibling_digest: Bytes20 = bytes20::new(
deserialize::deserialize_vector(encoded_proof, 20)
);
current_digest = node_hash(
current_digest,
sibling_digest
);
proofSize = proofSize - 1;
};
bytes20::data(&current_digest) == bytes20::data(&root)
}
// construct_proofs constructs a merkle tree and returns the root of the tree as
// a Bytes20 as well as the vector of encoded proofs
public fun construct_proofs(
messages: &vector<vector<u8>>,
depth: u8
) : (Bytes20, vector<u8>) {
if ( 1 << depth < vector::length(messages)) {
abort E_DEPTH_NOT_LARGE_ENOUGH_FOR_MESSAGES
};
// empty tree
// The tree is structured as follows:
// 1
// 2 3
// 4 5 6 7
// ...
// In this structure the parent of node x is x//2 and the children
// of node x are x*2 and x*2 + 1. Also, the sibling of the node x
// is x^1. The root is at index 1 and index 0 is not used.
let tree = vector::empty<Bytes20>();
// empty leaf hash
let cachedEmptyLeafHash: Bytes20 = empty_leaf_hash();
// Instantiate tree to be a full binary tree with the appropriate depth.
// Add an entry at the end for swapping
let i: u64 = 0;
while (i < (1 << (depth+1)) + 1){
vector::push_back(&mut tree, cachedEmptyLeafHash);
i = i + 1;
};
// Fill in bottom row with leaf hashes
let j: u64 = 0;
while (j < vector::length(messages)){
set_element<Bytes20>(&mut tree, leaf_hash(vector::borrow(messages, j)), (1 << depth) + j);
j = j + 1;
};
// Filling the node hashes from bottom to top
let k: u8 = depth;
while (k>0){
let level: u8 = k-1;
let levelNumNodes = 1 << level;
let i: u64 = 0;
while (i < levelNumNodes ){
let id = (1 << level) + i;
let node_hash = node_hash(*vector::borrow(&tree, id * 2), *vector::borrow(&tree, id * 2 + 1));
set_element<Bytes20>(&mut tree, node_hash, id);
i = i + 1;
};
k = k - 1;
};
let root = *vector::borrow(&tree, 1);
// construct proofs and create encoded proofs vector
let proofs = vector::empty<u8>();
let i: u64 = 0;
while (i < vector::length(messages)){
let cur_proof = vector::empty<u8>();
vector::push_back(&mut cur_proof, depth);
let idx = (1 << depth) + i;
while (idx > 1) {
vector::append(&mut cur_proof, bytes20::data(vector::borrow(&tree, idx ^ 1)));
// Jump to parent
idx = idx / 2;
};
vector::append(&mut proofs, cur_proof);
i = i + 1;
};
(root, proofs)
}
#[test]
fun testGreaterThan(){
// test 1
let x = bytes20::new(x"0000000000000000000000000000000000001000");
let y = bytes20::new(x"0000000000000000000000000000000000000001");
let res = greater_than(&x, &y);
assert!(res==true, 0);
res = greater_than(&y, &x);
assert!(res==false, 0);
// test 2
x = bytes20::new(x"1100000000000000000000000000000000001000");
y = bytes20::new(x"1100000000000000000000000000000000000001");
res = greater_than(&x, &y);
assert!(res==true, 0);
// equality case
x = bytes20::new(x"1100000000000000000000000000000000001001");
y = bytes20::new(x"1100000000000000000000000000000000001001");
res = greater_than(&x, &y);
assert!(res==false, 0);
}
#[test]
fun test_hash_leaf() {
let data: vector<u8> = x"00640000000000000000000000000000000000000000000000000000000000000000000000000000640000000000000064000000640000000000000064000000000000006400000000000000640000000000000064";
let hash = leaf_hash(&data);
let expected = bytes20::new(x"afc6a8ac466430f35895055f8a4c951785dad5ce");
assert!(hash == expected, 1);
}
#[test]
fun test_hash_node() {
let h1 = bytes20::new(x"05c51b04b820c0f704e3fdd2e4fc1e70aff26dff");
let h2 = bytes20::new(x"1e108841c8d21c7a5c4860c8c3499c918ea9e0ac");
let hash = node_hash(h1, h2);
let expected = bytes20::new(x"2d0e4fde68184c7ce8af426a0865bd41ef84dfa4");
assert!(hash == expected, 1);
}
#[test]
fun testMerkleTreeDepth1(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"1234");
let (root, proofs) = construct_proofs(&messages, 1);
let proofs_cursor = cursor::new(proofs);
let valid = is_proof_valid(&mut proofs_cursor, root, x"1234");
assert!(valid==true, 0);
// destroy cursor
cursor::take_rest<u8>(proofs_cursor);
}
#[test]
fun testMerkleTreeDepth2(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"1234");
vector::push_back(&mut messages, x"4321");
vector::push_back(&mut messages, x"11");
vector::push_back(&mut messages, x"22");
let (root, proofs) = construct_proofs(&messages, 2);
let proofs_cursor = cursor::new(proofs);
assert!(is_proof_valid(&mut proofs_cursor, root, x"1234")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"4321")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"11")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"22")==true, 0);
// destroy cursor
cursor::take_rest<u8>(proofs_cursor);
}
#[test]
fun test_merkle_tree_depth_3(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"00");
vector::push_back(&mut messages, x"4321");
vector::push_back(&mut messages, x"444444");
vector::push_back(&mut messages, x"22222222");
vector::push_back(&mut messages, x"22");
vector::push_back(&mut messages, x"11");
vector::push_back(&mut messages, x"100000");
vector::push_back(&mut messages, x"eeeeee");
let (root, proofs) = construct_proofs(&messages, 3);
let proofs_cursor = cursor::new(proofs);
assert!(is_proof_valid(&mut proofs_cursor, root, x"00")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"4321")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"444444")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"22222222")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"22")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"11")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"100000")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"eeeeee")==true, 0);
// destroy cursor
cursor::take_rest<u8>(proofs_cursor);
}
#[test]
fun test_merkle_tree_depth_1_invalid_proofs(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"1234");
let (root, proofs) = construct_proofs(&messages, 1);
let proofs_cursor = cursor::new(proofs);
// use wrong leaf data (it is not included in the tree)
let valid = is_proof_valid(&mut proofs_cursor, root, x"432222");
assert!(valid==false, 0);
// destroy cursor
cursor::take_rest<u8>(proofs_cursor);
}
#[test]
fun test_merkle_tree_depth_2_invalid_proofs(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"1234");
vector::push_back(&mut messages, x"4321");
vector::push_back(&mut messages, x"11");
vector::push_back(&mut messages, x"22");
let (root, proofs) = construct_proofs(&messages, 2);
let proofs_cursor = cursor::new(proofs);
// proof fails because we used the proof of x"1234" to try to prove that x"4321" is in the tree
assert!(is_proof_valid(&mut proofs_cursor, root, x"4321")==false, 0);
// proof succeeds
assert!(is_proof_valid(&mut proofs_cursor, root, x"4321")==true, 0);
// proof fails because we used the proof of x"11" to try to prove that x"22" is in the tree
assert!(is_proof_valid(&mut proofs_cursor, root, x"22")==false, 0);
// proof succeeds
assert!(is_proof_valid(&mut proofs_cursor, root, x"22")==true, 0);
// destroy cursor
cursor::take_rest<u8>(proofs_cursor);
}
#[test]
fun test_merkle_tree_depth_3_invalid_proofs(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"00");
vector::push_back(&mut messages, x"4321");
vector::push_back(&mut messages, x"444444");
vector::push_back(&mut messages, x"22222222");
vector::push_back(&mut messages, x"22");
vector::push_back(&mut messages, x"11");
vector::push_back(&mut messages, x"100000");
vector::push_back(&mut messages, x"eeeeee");
let (root, proofs) = construct_proofs(&messages, 3);
let proofs_cursor = cursor::new(proofs);
// test various proof failure cases (because of mismatch between proof and leaf data)
assert!(is_proof_valid(&mut proofs_cursor, root, x"00")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"22")==false, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"22222222")==false, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"22222222")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"22")==true, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"eeeeee")==false, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"4321")==false, 0);
assert!(is_proof_valid(&mut proofs_cursor, root, x"eeeeee")==true, 0);
// destroy cursor
cursor::take_rest<u8>(proofs_cursor);
}
#[test]
#[expected_failure(abort_code = pyth::merkle_tree::E_DEPTH_NOT_LARGE_ENOUGH_FOR_MESSAGES)]
fun test_merkle_tree_depth_exceeded_1(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"00");
vector::push_back(&mut messages, x"4321");
vector::push_back(&mut messages, x"444444");
construct_proofs(&messages, 1); //depth 1
}
#[test]
#[expected_failure(abort_code = pyth::merkle_tree::E_DEPTH_NOT_LARGE_ENOUGH_FOR_MESSAGES)]
fun test_merkle_tree_depth_exceeded_2(){
let messages = vector::empty<vector<u8>>();
vector::push_back(&mut messages, x"00");
vector::push_back(&mut messages, x"4321");
vector::push_back(&mut messages, x"444444");
vector::push_back(&mut messages, x"22222222");
vector::push_back(&mut messages, x"22");
construct_proofs(&messages, 2); // depth 2
}
}