using System;
public class Program
{
public static void Main()
//Convert SOID to bytes
var buffer = BitConverter.GetBytes(123456733333); //Enter SOID
var bytes=Convert.ToBase64String(buffer);
Console.WriteLine(bytes);
//bytes (encoded) to SOID
var newBytes = Convert.FromBase64String(bytes);
Console.WriteLine(BitConverter.ToInt64(newBytes));
}