static bool WIFPassedChecksum(string key)
{
var decoded = Encoders.Base58Decode(key);
var checksum = decoded.Skip(decoded.Count() - 4).Take(4).ToArray();
var keyBytes = decoded.Take(decoded.Count() - 4).ToArray();
var newChecksum = Encoders.DoubleSHA256(keyBytes).Take(4).ToArray();
return(newChecksum.SequenceEqual(checksum));
}