Three college students were ordered by a federal judge to call off a presentation at a computer hackers’ Sunday assembly where they intended to reveal security errors in the automated charge system used by Boston’s subway.

Furthermore, the temporary restraining order, issued by a U.S. district judge in Massachusetts, precluded the students from the Massachusetts Institute of Technology from showing at the Defcon conference held in Las Vegas how to benefit from the weaknesses of the system in order to travel for free, The Associated Press reported.

Jennifer Granick, the Electronics Frontier Foundation’s civil liberties director, informed the AP that her group, which is representing the three MIT students Zack Anderson, R.J. Ryan and Alessandro Chiesa, intends to appeal the court order.

The Massachusetts Bay Transportation Authority explained in a complaint filed on Friday that the MIT students suggested to explain those interested how to use the hacks, without giving the transit system any time to repair the flaws. On the other hand, Jennifer Granick told the AP that the students intended no more than sharing their findings and that they would have not divulged any information that would have facilitated the work of those who planned on hacking the payment system.

Some electronic copies of the presentation have been circulating on the Internet and they ridiculed the physical security of the transit, showing unlocked doors or exposed computer monitors in subway stations.

Moreover, as reported by the AP, the 87-slide presentation was handed out to conference participants on CDs on Thursday, even before the conference began.

“It is extremely important to maintain the security and integrity of the Fare Media systems,” Gary Foster, chief technology officer for the transit system, said in a court statement, as quoted by the same source. “With an insecure, compromised system, even basic revenue controls, to name one example, become significantly challenging,” he added.