<PackageReference Include="BouncyCastle.Cryptography" Version="2.6.0" />

Org.BouncyCastle.Crypto.Digests.KeccakDigest

public class KeccakDigest : IDigest, IMemoable
Implementation of Keccak based on following KeccakNISTInterface.c from http://keccak.noekeon.org/
namespace Org.BouncyCastle.Tls { }