Anonymous file sharing does not create Fourth Amendment privacy when a user voluntarily exposes information to strangers on a public peer-to-peer network. In United States v. Johnson, the 1st Circuit ruled investigators did not conduct a search when they collected and analyzed the defendant’s exposed IP address and file requests. The case distinguishes anonymity tools from a legally reasonable expectation of privacy.
United States v. Johnson, 2026 WL 1959441 (1st Cir. 2026)
Technology changes rapidly, but one Fourth Amendment principle remains consistent: If you knowingly expose information to the public, you generally cannot claim a reasonable expectation of privacy in that information. Eric Robert Johnson discovered that the hard way.
Johnson used Freenet, a peer-to-peer file sharing network designed to provide users with a degree of anonymity. Rather than storing files on centralized servers, Freenet distributes information among thousands of connected computers.
Using a tool called Freenet Roundup, which tracks and logs data transfers on Freenet’s peer-to-peer system, law enforcement investigators traced requests for child sex abuse material (CSAM) files to Johnson’s IP address. The FBI obtained a warrant and searched Johnson’s home, finding electronic devices and external drives that contained additional material.
“The court concluded Johnson voluntarily exposed his IP address information to anyone participating in the network, including law enforcement.”
Johnson requested suppression of the data captured by Freenet Roundup, arguing it constituted a “presumptively unreasonable [search] without a warrant.” When that motion was denied, he entered a conditional guilty plea to CSAM possession, reserving the right to appeal the result of his motion to suppress. He received 120 months in prison and five years of supervised release. After sentencing, he appealed the conviction.
Before the 1st Circuit, Johnson argued that because he was using software intended to protect his identity, the use of Freenet Roundup by law enforcement without a warrant violated the Fourth Amendment. The court didn’t buy his argument.
Johnson chose to operate Freenet in what is known as Opennet mode (vs. the more secure Darknet mode). In that configuration, his computer automatically accepted connections from strangers on the internet and exchanged information with computers it had never interfaced with before. The court concluded Johnson voluntarily exposed his IP address information to anyone participating in the network, including law enforcement. Investigators did not hack his computer, bypass security measures, or remotely search the contents of his hard drive. Instead, they simply received and analyzed information Johnson’s own computer transmitted across a publicly accessible network. Under those circumstances, the court held Johnson had no objectively reasonable expectation of privacy in those communications.
A Fourth Amendment search generally occurs when officers intrude into an area where a person has a reasonable expectation of privacy. But when a suspect voluntarily shares information with the public, or with an unknown group of network users, that expectation often disappears. The fact that the suspect hopes to remain anonymous does not necessarily mean the information is legally private.
For officers, Johnson teaches two practical lessons. First, understanding how a technology actually works is often just as important as understanding the law. Second, courts continue to distinguish between obtaining information that a suspect voluntarily exposes to others and intruding into private digital storage. The first may not constitute a Fourth Amendment search at all. The second almost always requires a warrant or another recognized exception.
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Taken together with United States v. González-Arocho (which I have also commented on), the Johnson case illustrates two sides of the same constitutional coin. Courts remain protective of the privacy interests people retain in their personal electronic devices, but they are equally clear that the Fourth Amendment does not shield information that individuals knowingly place into the public digital marketplace. Understanding where that line is drawn can make the difference between evidence that is admitted and evidence that is suppressed.
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