Schneier's metrocard cracked

I heard on the radio that the security scheme used in New York City metrocards (designed with much input frm Bruce Schneier) has been cracked and that the "hackers" can now add fare to the cards. Does anyone know any details? What encryption did Schneier use? --- Dr.Dimitri Vulis KOTM Brighton Beach Boardwalk BBS, Forest Hills, N.Y.: +1-718-261-2013, 14.4Kbps