Sign documents with standard encryption for QR-code Leave feedback

using (Signature signature = new Signature("sample.pdf"))
{
    // setup key and passphrase
    string key = "1234567890";
    string salt = "1234567890";
    // create data encryption
    IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.AES, key, salt);
    // setup QR-Code options
    QrCodeSignOptions options = new QrCodeSignOptions()
    {
        // set QR-code text
        Text = "This is secure text that will be encrypted",
        // QR-code type
        EncodeType = QrCodeTypes.QR,
        // specify serialization encryption
        DataEncryption = encryption,
        // locate and aligh signature
        Height = 100,
        Width = 100,
        VerticalAlignment = VerticalAlignment.Bottom,
        HorizontalAlignment = HorizontalAlignment.Right,
        Margin = new Padding() { Right = 10, Bottom = 10 }
    };
    // sign document to file
    signature.Sign("QrCodeEncrypted.pdf", options);
}