<PackageReference Include="BouncyCastle.Cryptography" Version="2.8.0-beta.349" />

Org.BouncyCastle.Crypto.Engines.XChaCha20Engine

Implementation of Daniel J. Bernstein's XChaCha20 stream cipher - ChaCha20 with an extended nonce.
namespace Org.BouncyCastle.Crypto.Engines { public class XChaCha20Engine : ChaCha7539Engine { public XChaCha20Engine(); } }