Lib.rs

smt-circom

This crate provides a Sparse Merkle Tree implementation in Rust using Poseidon hash, compatible with circom zero-knowledge proofs.

It can be used with an in-memory node store, a persistent RocksDB store, or a custom store.

The implementation is inspired by @iden3/js-merkletree.

Example usage

use smt_circom::{store::MemStore, SparseMerkleTree};

let mut tree = SparseMerkleTree::<64, _>::new(MemStore::new())?;
assert_eq!(tree.root()?, [0; 32]);
let (idx, new_value) = ([1; 32], [2; 32]);
let proof = tree.get_proof(idx);
assert!(!proof.membership);
tree.add_or_update(idx, new_value)?;

Benchmark results

Here's the result of running a benchmark on an AMD Ryzen 5 5600H, comparing smt-circom against @iden3/js-merkletree (Node.js), both using trees with depth 64 and an in-memory store. It first adds 10 random leafs, then gets inclusion proofs for these 10 leafs (both benchmarks use the same seeded rng).