An MIT student project showing how anyone with a magnetic card writer can ride the Boston subway for free was not presented at this summer’s DEF CON hacker convention because of an emergency court order. But details sufficient to repeat the attack were published in open court documents by the Massachusetts Bay Transit Authority in its request for a restraining order.

Three MIT students will not be presenting their security research at the annual DEF CON hacker convention this weekend because of a temporary restraining order filed by the Massachusetts Bay Transportation Authority on Friday afternoon. The students — legally represented by the Electronic Frontier Foundation, a nonprofit advocacy group — are appealing the order.