internal void DeriveSharedPingPongHmacKey(InviteRequestPacket req, InviteAck1Packet ack1, InviteAck2Packet ack2, InviteConfirmationPacket cfm)
{
if (SharedInviteAckDhSecret == null)
{
throw new NotImplementedException();
}
PacketProcedures.CreateBinaryWriter(out var ms, out var w);
req.GetSharedSignedFields(w);
ack1.GetSharedSignedFields(w, true);
ack2.GetSharedSignedFields(w);
cfm.GetSharedSignedFields(w);
w.Write(SharedInviteAckDhSecret);
SharedPingPongHmacKey = _localDrpPeer.CryptoLibrary.GetHashSHA256(ms.ToArray());
}
