verify_merkle_branch.java

  public static boolean verify_merkle_branch(
      Bytes32 leaf, List<Bytes32> proof, int depth, int index, Bytes32 root) {
    Bytes32 value = leaf;
    for (int i = 0; i < depth; i++) {
      if (Math.floor(index / Math.pow(2, i)) % 2 != 0) {
        value = Hash.sha2_256(Bytes.concatenate(proof.get(i), value));
      } else {
        value = Hash.sha2_256(Bytes.concatenate(value, proof.get(i)));
      }
    }
    return value.equals(root);
  }