private Rsa GetRsa() { var privateKeyBytes = Convert.FromBase64String(base64PrivateKey); var parameters = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(privateKeyBytes); #if NETSTANDARD return new RsaStandard(parameters); #else var rsaCsp = new RSACryptoServiceProvider(); rsaCsp.ImportParameters(DotNetUtilities.ToRSAParameters(parameters)); return rsaCsp; #endif }