/// <summary>
/// constructs a new RSA object
/// </summary>
public RSA(int keySize = -1)
{
_keySize = keySize != -1 ? keySize : _rsa.LegalKeySizes?[0].MaxSize ?? _rsa.KeySize;
//foreach(var s in _rsa.LegalKeySizes)
// Log.i("Min:{0}, Max:{1}, Skip:{2}", s.MinSize, s.MaxSize, s.SkipSize);
_rsa.KeySize = _keySize;
PrivateKey = _rsa.ExportParameters(true);
PublicKey = _rsa.ExportParameters(false);
}