Playpen, “the largest remaining known child pornography hidden service in the world” that exploited extreme child abuse, was shut down by the FBI in 2015, but only after the service ran for 12 days from FBI servers in Virginia so all activity could be monitored.
The FBI exploited a vulnerability in the Tor browser to hack users’ computers and collect IPs. The operation led to 1,500 arrests across the United States by matching the material to user IP addresses.
At the time, some judges doubted the constitutionality of the warrants issued to bring down the network, claiming they did not respect the Fourth Amendment of the US Constitution in terms of unlawful searches and seizures.
Lawyers representing the Department of Justice are now calling for dismissal of a Playpen case from federal court, because they are not yet willing to declassify information about the methods used to hack the browser.
“The government must now choose between disclosure of classified information and dismissal of its indictment. Disclosure is not currently an option,” said the filing released in Washington on Friday.
It’s not the first time the Bureau refuses to reveal the malware code it used to hack Tor. “Unwillingness to disclose” is also why judges threw out evidence in the Jay Michaud case, a Vancouver public school worker tied to the Playpen scandal.