using System;

using System.Security.Cryptography;

public class Program

{

    public static void Main()

    {

        string parameter = "{\"action\":\"newmobile\",\"AHMITISM030_Area\":\"IT\",\"ahmitism030_kategori\":\"REQUEST\",\"AHMITISM030_vphone\":\"344343\",\"AHMITISM030_select_vsite\":\"P4\",\"ahmitism030_LayananITvalue\":\"SOFTWARE AND APPLICATION\",\"AHMITISM030_vitem\":\"MAINTAIN POWER BI\",\"AHMITISM030_vsummary\":\"Entry Down Payment Request\",\"AHMITISM030_vdesc\":\"testimage\",\"AHMITISM030_vhit\":\"BOT\",\"AHMITISM030_vdept\":\"SOFTWARE ENGINEERING DEPARTMENT\",\"AHMITISM030_vdeptid\":\"50040331\",\"AHMITISM030_vdiv\":\"INFORMATION TECHNOLOGY DIVISION\",\"AHMITISM030_vdivid\":\"50000777\",\"AHMITISM030_vemail\":\"patrick.a.lerapatty@astra-honda.com\",\"AHMITISM030_vattfilecontents\":\"\"}";

        string userId = "admin";

        var reqParamString = System.Text.Json.JsonSerializer.Serialize(new

                                                                       {

                                                                           Parameters = parameter,

                                                                           UserId = userId

                                                                       });

​

        using (HMACSHA256 hmac = new HMACSHA256(System.Text.Encoding.UTF8.GetBytes("8qmSs8RdffQiir4RclzAeL6JCMGg2Ee9lOvvMiu8tDV65w75IzFklNQc15Zmszm8")))

        {

            byte[] computedHash = hmac.ComputeHash(System.Text.Encoding.ASCII.GetBytes(reqParamString));

            Console.WriteLine(Convert.ToBase64String(computedHash));

        }

    }

}