A federal judge on Tuesday lifted a temporary injunction that prevented three MIT students from discussing security flaws in Boston's transit fare card system.

The judge also rejected the Massachusetts Bay Transit Authority's request for a five-month injunction to keep the students quiet while the transit agency fixed its security problems. The MBTA's court filings indicate that the agency needs five months to secure its fare system.

The MBTA's lawsuit against the students' claims that the students' planned presentation would facilitate fraud, in violation of the Computer Fraud and Abuse Act. The MBTA's legal team argues that contrary to public assertions, the students did defraud the Boston transit system and that "... the damage affects a computer system used by a government entity for national security purposes."

But according to Marcia Hofmann, staff attorney at the Electronic Frontier Foundation, which is representing the students as part of its Coders' Rights Project, the judge "correctly found that it was unlikely that the CFAA would apply to security researchers giving an academic talk."

Cyberliberties advocates condemned the gag order when it was issued.

The initial injunction was granted on Saturday, Aug. 9, the day before the MIT students -- Zack Anderson, R.J. Ryan, and Alessandro Chiesa -- planned to present information about security flaws in the MBTA system in a session at the Defcon security conference in Las Vegas.

The student's presentation materials have been posted online. They reveal flawed network and physical security, social engineering weaknesses, and exposed information that could be used to compromise the Boston transit system. Among the images included in the presentation are gates left unchained, accessible turnstile control boxes, computer screens visible through windows, door keys left in open boxes, documents left in public view, and unattended surveillance stations.

The students have withheld key information required to successfully hack MBTA fare cards, including custom software they wrote in the course of their research. They maintain they were not going to release this information to the public.

On Tuesday, the EFF applauded the removal of the injunction.

"We're very pleased that the court recognized that the MBTA's legal arguments were meritless," said EFF legal director Cindy Cohn in a statement. "The MBTA's attempts to silence these students were not only misguided, but blatantly unconstitutional."

The MBTA's lawsuit against the students nonetheless continues.