In December 2014, the FBI received a tip from a foreign law enforcement agency that a Tor Hidden Service site called “Playpen” was hosting child pornography. That tip would ultimately lead to the largest known hacking operation in U.S. law enforcement history.
The Playpen investigation—driven by the FBI’s hacking campaign—resulted in hundreds of criminal prosecutions that are currently working their way through the federal courts. The issues in these cases are technical and the alleged crimes are distasteful. As a result, relatively little attention has been paid to the significant legal questions these cases raise.