1. Hyrax. https://github.com/hyraxZK. Hyrax. https://github.com/hyraxZK.
2. libsecp256k1. https://github.com/apoelstra/secp256k1-mw/tree/bulletproofs. libsecp256k1. https://github.com/apoelstra/secp256k1-mw/tree/bulletproofs.
3. libsnark. https://github.com/scipr-lab/libsnark. libsnark. https://github.com/scipr-lab/libsnark.
4. PyPy. https://pypy.org. PyPy. https://pypy.org.