LIKE his favorite pop singer Joshua, Petrus Pangkur also uses the designation, "Boni Diobok-obok", or Boni Messes Around, for his business.  Indeed, this 22-year-old has made it one of his hobbies to mess things up. His particular specialty is the world of virtual reality.  But Petrus has not been as lucky as his idol Joshua.  Two weeks ago, Petrus and three other crackers—people who hack into credit card informatio