This is a simple sha256 hash algorithm based on Go's implementation: https://cs.opensource.google/go/go/+/refs/tags/go1.23.0:src/crypto/sha256/sha256.go which has the copyright notice:
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
The code has been updated to support compiler:
$ moon version --all
moon 0.1.20241111 (e6d64e0 2024-11-11) ~/.moon/bin/moon
moonc v0.1.20241111+dc2407357 ~/.moon/bin/moonc
moonrun 0.1.20241111 (e6d64e0 2024-11-11) ~/.moon/bin/moonrunUse moonup to manage moon compiler versions:
https://github.com/chawyehsu/moonup