public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public static CLASS_CrrtAndKeys VAR_CertAndKeys;
        public static String VAR_TestJsonString = String.Empty;

        private void button_ToJson_Click(object sender, EventArgs e)
        {
            // Convert to JSON String
            VAR_CertAndKeys = new CLASS_CrrtAndKeys();

            if (checkBox_Cert.Checked) VAR_CertAndKeys.Cert = textBox_Cert.Text;
            if (checkBox_Key1.Checked) VAR_CertAndKeys.Key1 = textBox_Key1.Text;
            if (checkBox_Key2.Checked) VAR_CertAndKeys.Key2 = textBox_Key2.Text;
            VAR_TestJsonString = JsonSerializer.Serialize(VAR_CertAndKeys);
            textBox_JsonString.Text = VAR_TestJsonString;
            richTextBox_Log.AppendText("JSON serialize....\n");
            richTextBox_Log.AppendText("  " + VAR_TestJsonString + "\n");
            richTextBox_Log.ScrollToCaret();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            VAR_CertAndKeys = new CLASS_CrrtAndKeys();
        }

        private void button_ParseJson_Click(object sender, EventArgs e)
        {
            // Parse 
            String _JsonStr = textBox_JsonString.Text;
            CLASS_CrrtAndKeys VAR_CertAndKeysDecode = JsonSerializer.Deserialize<CLASS_CrrtAndKeys>(_JsonStr);
            richTextBox_Log.AppendText("JSON deserialize....\n");
            richTextBox_Log.AppendText("  Certification: " + VAR_CertAndKeysDecode.Cert + "\n");
            richTextBox_Log.AppendText("  Key 1: " + VAR_CertAndKeysDecode.Key1 + "\n");
            richTextBox_Log.AppendText("  Key 2: " + VAR_CertAndKeysDecode.Key2 + "\n");
            richTextBox_Log.ScrollToCaret();
        }
    }

    public class CLASS_CrrtAndKeys
    {
        public string Cert { get; set; }
        public string Key1 { get; set; }
        public string Key2 { get; set; }
    }