The judge who authorized the FBI to hack 1,300 dark web users under a single warrant seems to be pretty confused about how the anonymity software Tor works. Newly unsealed documents suggest that the confusion stems from the US Department of Justice's own arguments.

In the documents, the DOJ argues that Tor users have no reasonable expectation of privacy when it comes to their IP address. This is the same argument that the judge used to justify the FBI implanting malware onto a dark web site in order to grab user IP addresses. It's also a counterintuitive point to make given that masking a computer's IP address is the whole point of using Tor.

The argument comes from the case of Jay Michaud, a public school employee in Vancouver, WA accused of accessing images of child abuse on a now-defunct hidden site called Play Pen, which the FBI seized and controversially continued running from its own server for 13 days. The Bureau hacked the computers of anyone accessing child abuse images on the seized site using malware called a Network Investigative Technique, or NIT, which infected the connecting machines and transmitted their true IP addresses back to the FBI.

One of the biggest issues raised in the case is whether a person using Tor has a reasonable expectation of privacy when it comes to their true IP address, which identifies users.