unique radom string

  private static string uniquestring(string bomEmailId)
    {
        using (MD5 md5 = MD5.Create())
        {
           //byte[] hash = md5.ComputeHash(Encoding.Default.GetBytes(bomEmailId));
            byte[] array = Encoding.ASCII.GetBytes(bomEmailId);
            Guid result = new Guid(array);
            return result.ToString();
        }
    }