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United States v. Johnson

2026-07-07

Authorities cited

Opinion

majority opinion

United States Court of Appeals

For the First Circuit

No. 24-1467

UNITED STATES,

Appellee,

v.

ERIC ROBERT JOHNSON,

Defendant, Appellant.

APPEAL FROM THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF MASSACHUSETTS

[Hon. Denise J. Casper, U.S. District Judge]

Before

Gelpí, Thompson, and Montecalvo,

Circuit Judges.

Christine DeMaso, Assistant Federal Public Defender, for

appellant.

Randall E. Kromm, Assistant United States Attorney, with whom

Leah B. Foley, United States Attorney, was on brief, for appellee.

July 7, 2026

THOMPSON, Circuit Judge.

Overview

In the current era of technology, there are myriad ways

for people to share content and information with each other. One

such way is to participate in peer-to-peer, file-sharing networks,

like LimeWire, BitTorrent, or, pertinent to this case, Freenet.

These publicly-available, internet-based platforms are a

conglomerate of files that users can download from, upload to, and

share with each other. Freenet, in particular, advertises as a

network that preserves its users' anonymity, thereby providing

them a more privatized means to share files. And, as a result,

some choose to abuse the platform by circulating illicit content.

Well, in the present case, appellant Eric Robert

Johnson's Freenet activity led to his conviction in the District

of Massachusetts for possessing child pornography. But since the

pretrial phase, Johnson has maintained that the government's bust

violated the Fourth Amendment, and he's sought to suppress all

evidence derived from the bust. Unable to sway the district court

in his favor, however, Johnson decided to plead guilty and rehash

the suppression issue before us.

So, we lay out everything in detail below, including our

reasons for why the district court is affirmed.

- 2 -I. Background

We pull our facts from the district court's decision and

from the evidentiary hearing, "presenting them in the light most

compatible with [the district court's] ruling." United States v.

McGregor, 650 F.3d 813, 816 (1st Cir. 2011) (citation modified).

a. Freenet

Before getting into what happened in Johnson's case, we

need to lay some groundwork about Freenet and its mechanics to

understand today's issues. Freenet is an internet-based,

peer-to-peer, file-sharing network that focuses on preserving its

users' anonymity. The Freenet software is publicly-available and

free, and thus it can be downloaded and installed by anyone.

Freenet's file sharing operates through a network of linked

computers (or "nodes") that break down data into fragments (or

"blocks"), encrypts those fragments, and randomly distributes them

among its users' nodes for storage.1 This breakdown process occurs

when a user uploads a file onto Freenet. After Freenet distributes

the data blocks to a user's nodes for storage, it then generates

an index (or "manifest") that lists all the blocks of the file and

1 Freenet does not store complete files in one place, and,

once broken down into blocks, users cannot decrypt the individual

blocks to view the content stored on their devices. At most, the

users are able to see there is an encrypted block in their data

cache.

- 3 -a "manifest key"2 that can be used to locate the blocks so it can

"reconstruct" the file for download. To reconstruct and download

files on Freenet, users share manifest keys through various means,

such as email, text, or posting them on online forums.

How does the reconstruction process work? To download

a file, a user inputs a manifest key into Freenet and doing so

signals the user's node to initiate the hard work. The node first

sends out requests to the user's peers -- neighboring nodes -- for

the data blocks.3 As our usage of "requests" (plural) suggests,

the Freenet software doesn't contact one sole peer to retrieve the

data blocks. The requests are divvied up (in roughly equal parts)

and sent out to several of the user's peers. If the

receiving-peer's node does not have the respective data block, it

will "relay" the request to a group of its peers to help it gather

its portion of the requested data blocks (again, with the work

divided evenly). Each time a request is sent out is called a

"hop," and Freenet will cap a request at no more than 18 hops. We

say "no more than" because Freenet attempts to conceal the original

requestor's identity by randomizing the maximum number of hops for

each download, however, that number never exceeds 18.

2 Each

manifest key is made up of a series of letters, numbers,

and special characters.

3Data blocks are identified by their "hash value[s]" which

is, in essence, a unique digital signature for each block.

- 4 -Freenet is operable in either "Darknet" or "Opennet"

mode, based on each user's choice. In the more private and

anonymized Darknet mode, a user's computer will connect only to

peers selected by that user. But in the less-protected Opennet

mode, a user's computer will connect to unknown peers (strangers)

on the whole of Freenet's worldwide network (where Freenet is

legal, of course). Freenet does not conceal a user's IP address

when their node connects to a neighboring node, thus strangers can

view an Opennet user's IP address whenever they connect.

Upon the download and installation of Freenet, users are

warned explicitly before choosing an operation mode that, in low

security Opennet mode, "an attacker with moderate resources may be

able to trace [the user's] activity on Freenet back to [the user]."4

It further warns (on another screen) that in low security mode,

"[i]t may be quite easy for others to discover [the user's]

identity." Freenet also reminds users throughout the file

downloading process that they are operating in low security mode

4 One more caveat is worth noting. Opennet mode can operate

in either "low security" or "normal security" mode. By choosing

low security mode, the user agrees that they "do not care about

monitoring and want [Freenet's] maximum performance." By choosing

normal security mode, the user agrees that they "live in a

relatively free country, but [they] would like to make it more

difficult for others to monitor [their] communications." Also,

when selecting normal mode, Freenet warns that it "will be

reasonably careful to protect [the user's] anonymity, at some

performance cost. [The user] should add friends running Freenet

and upgrade to [Darknet mode] when [they] are able."

- 5 -and to "[b]e careful" when opening a newly-downloaded file because

"it might cause your web browser or other software to breach your

anonymity[] [or] give away your IP address."

b. Freenet Roundup

Freenet's anonymity features make it alluring to those

who want to share and retrieve illicit materials, such as child

sexual abuse material ("CSAM"), online. To combat this problem,

Dr. Brian Levine -- a professor at the University of

Massachusetts -- created "Freenet Roundup," a law enforcement tool

that can identify and trace CSAM file-sharing on Freenet. Freenet

Roundup is a modification of Freenet that operates in Opennet mode

and is available only to law enforcement officers. When using

Freenet Roundup, an officer's node operates as would a normal peer

in the Freenet network. Thus, the officer's node receives and

relays strangers' requests for data blocks like a typical Freenet

user. The difference with Freenet Roundup is that it logs requests

it receives and filters them through a two-step process.

At the first step, the law enforcement node looks at the

"Hops to Live" counter for the request -- which shows the remaining

number of hops out of the possible 18-hop maximum -- to determine

whether it has 16 or more hops remaining.5 If at least 16 hops do

remain, the request proceeds to step two of filtering. At step

5Requests with less than 16 hops are not of interest because

they are highly unlikely to have come from an original requestor.

- 6 -two, the flagged requests are sent to a server managed by

Pennsylvania's Internet Crimes Against Children Task Force

("ICAC") to determine whether the requests were made for a known

CSAM file. The ICAC has a library of data blocks identified as

CSAM and compares their hash values with the blocks in the flagged

requests. If there's no match, there's no further processing of

that request. If there is a match, though, the request information

is entered into a spreadsheet that employs a formula to determine

whether its sender was the original requestor or merely a relayer

of another user's request.6 The request information includes the

timestamp (date and time) of when it was made, the number of

remaining hops, the number of peers in the node's network, and the

node's IP address.7 The information is then sent to the appropriate

jurisdiction for further investigation based on the geolocation

for the respective IP address.

c. The Arrest

Eric Robert Johnson was one of the Freenet users caught

in the web of Freenet Roundup. An investigation ensued after

Federal Bureau of Investigations ("FBI") Special Agent Bryce

Dr. Levine stated in his testimony that his report revealed

6

the false positive rate for identifying these matches as requestors or relayers has been no more than 2.3 percent.

The node's number of peers, IP address, and the request's

7

remaining number of hops are all transmitted when using the Freenet software in the normal course.

- 7 -Montoya was tipped off that Freenet Roundup identified a user (with

an IP address that was later determined to be Johnson's) sent out

three different requests for CSAM data blocks between May 29 and

June 8, 2021.8 In February of 2022, Agent Montoya successfully

applied for a search warrant for Johnson's residence in Billerica,

Massachusetts, aiming to find evidence of his possession and

receipt of child pornography.9 FBI agents executed the search,

and it yielded positive results. They found two laptops (at least

one of which that had the Freenet software downloaded), a tablet,

and multiple external hard drives (at least one of which that had

contained CSAM).

So, naturally (as they say), he caught a case, and we

now move on to recall the juridical play-by-play.

II. Procedural History

Johnson was charged with one count of possession of child

pornography in violation of 18 U.S.C. § 2252(a)(5)(B), (b)(2).

During the pretrial phase, Johnson moved the court to suppress all

8 To trace the IP address back to its owner, law enforcement

first determined that Verizon serviced the IP address. Thereafter, the FBI subpoenaed Verizon for the subscriber information, which

was registered under Johnson's name and Billerica address.

9 In the affidavit, Agent Montoya explained the operations of

both Freenet and Freenet Roundup, and, from the evidence the FBI

had gathered and reviewed, that he believed a user with an IP

address registered to Johnson had sent out three different requests for CSAM files. Agent Montoya also described the content of the

sought-after files.

- 8 -the evidence derived from law enforcement's use of Freenet Roundup.

He kicked off his motion by arguing that the FBI's use of its tool

to monitor Freenet and track his activity constituted a Fourth

Amendment search and that he had an expectation of privacy in the

requests he sent out on the platform.

To strengthen his challenge, Johnson said the

government's conduct was in contradiction to Kyllo v. United

States, 533 U.S. 27 (2001), being that it was only able to obtain

the at-issue evidence by using "sophisticated technology that is

not in general public use," which made the purported search

"presumptively unreasonable without a warrant." He also compared

law enforcement's warrantless use of Freenet Roundup with its

warrantless procurement of cell phone site information which the

Supreme Court deemed unconstitutional in Carpenter v. United

States, 585 U.S. 296 (2018).

In harmony with the Fourth Amendment framework for

answering these types of questions (fret not, we'll break this

down in more detail below), the remainder of Johnson's suppression

arguments can be placed in two categories: subjective and objective

expectations of privacy. We'll start with the former, the

subjective variant.

For this prong of his argument, Johnson explained that

a Freenet user relies on the software to provide anonymity, and

the limited data revealed through transmissions are a "dint of its

- 9 -operation," id. at 315, that allows Freenet to perform its

functions. A single node, Johnson said, cannot determine "the

overall structure of the network and identify individual users."

Thus, a user's subjective expectation of privacy in their Freenet

transmissions is violated when the government deploys its Freenet

Roundup tool to track activity "on the network, assemble the data,

and analyze it using special law enforcement-only software."

As to his claim of having an objective expectation of

privacy, Johnson focused on the process law enforcement undertook

to distinguish requestor nodes from relayer nodes (explained

above). He argued the "requirements and resources necessary to

de-anonymize Freenet users" make it "out-of-reach to all but state

actors." He supported his claim with a forensic report prepared

by Michael Miglianti,10 who described the "significant research and

validation resources" the government used to create Freenet

Roundup and explained how such techniques "are vastly different

than the resources associated with a typical Freenet user."11

10Miglianti is an expert witness with "years of experience

in the digital forensics and cyber-security fields" who Johnson

called upon to testify at trial.

Miglianti stated (in his report) that the Freenet "software

11

is freely available," "easily downloaded from the website," and

"requires minimal user time and effort." He contrasted this

near-burdenless process with Freenet Roundup for which "significant resources have been expended" to develop.

- 10 -In its opposition to the suppression motion, the

government argued Johnson failed to establish a subjective and

objective expectation of privacy in his Freenet transmissions. It

challenged Johnson's contention that his "mere use of Freenet, as

a file sharing platform specifically aimed at anonymizing its

users, alone[,] manifests a reasonable expectation of privacy[.]"

The government said Johnson lacked a reasonable expectation of

privacy when he "voluntarily shared requests for child pornography

files with an unknown collection of strangers on Freenet," homing

in on the rule that a person does not have a reasonable expectation

of privacy in information voluntarily disclosed to third parties.

And it further emphasized that Johnson chose to use Freenet in

Opennet mode, which warned him that his IP address "would be shared

with many virtual strangers."

Additionally, the government pointed to a breadth of

cases that held a person does "not have an expectation of privacy

with their peer-to-peer activity on the Internet." And it

ultimately sought to align Johnson's case with United States v.

Pobre, No. 8:19-CR-348-PX, 2022 WL 1136891 (D. Md. Apr. 15, 2022),

which determined the government's use of Freenet Roundup didn't

violate the Fourth Amendment because a Freenet user operating in

Opennet mode lacks an expectation of privacy in their activity on

the software.

- 11 -All things considered, the district court ultimately

agreed with the government and denied Johnson's motion to suppress,

reasoning that he lacked a reasonable expectation of privacy in

his Freenet activity. Despite Johnson's choice "to participate in

a peer-to-peer network designed to allow censorship-resistant

communication and with measures to protect anonymity," the court

said, Freenet "warned any user that [their] identification could

be discovered and that the choice of Opennet will allow connections

with strangers (which could or could not be law enforcement)."

The court distinguished "the wholesale cataloguing and disclosure

of cell site location information in Carpenter" from Freenet

Roundup, "which essentially logs the block requests that are likely

to contain suspected CSAM." Though law enforcement employed a

modified version of Freenet, as the court explained, it operated

"in a forum where Johnson already ha[d] no reasonable expectation

of privacy." Accordingly, Freenet Roundup allowed agents to "act[]

like an undercover officer crashing a public meeting." Pobre,

2022 WL 1136891, at *6. Lastly, the court acknowledged that it

was persuaded by "cases rejecting similar challenges to

traditional peer-to-peer networks[,]" and it found Pobre to be on

point with Johnson's case.

Following the district court's order and some additional

trial preparation, Johnson opted for a conditional guilty plea

that preserved his right to appeal the court's suppression ruling.

- 12 -Thereafter, the court sentenced him to 120 months' imprisonment

and five years' supervised release. He timely appealed, and here

we are.

III. Standard of Review

We embark on a bifurcated review for appeals of a

district court's denial of a suppression motion. See United States

v. Tiru-Plaza, 766 F.3d 111, 114 (1st Cir. 2014). Factual and

credibility determinations are assessed for clear error, and for

such determinations, "we grant significant deference to the

district court, overturning its finding only if, after a full

review of the record, we possess 'a definite and firm conviction'

that a mistake was made." Id. at 114-15 (quoting McGregor, 650

F.3d at 820). The district court's legal conclusions, however,

garner de novo review. United States v. Camacho, 661 F.3d 718,

724 (1st Cir. 2011). The "ultimate decision to grant or deny [a]

motion to suppress" qualifies as a legal conclusion subject to de

novo review. United States v. Centeno-González, 989 F.3d 36, 44

(1st Cir. 2021) (citation modified).

IV. Discussion

Johnson's claims of error closely track his arguments

below. But before diving in, we'll tease out the relevant legal

rules of the Fourth Amendment.

- 13 -a. The Fourth Amendment's Shield

Our exposé begins with the bedrock principle that the

Fourth Amendment protects "[t]he right of the people to be secure

in their persons, houses, papers, and effects, against

unreasonable searches and seizures." U.S. Const. amend. IV. At

bottom, this Amendment is intended "to safeguard the privacy and

security of individuals against arbitrary invasions by

governmental officials." Carpenter, 585 U.S. at 303 (quoting

Camara v. Mun. Ct. of City & Cnty. of S.F., 387 U.S. 523, 528

(1967)). A government actor searching one's home is "presumptively

unreasonable" in the absence of a warrant supported by probable

cause. See United States v. Karo, 468 U.S. 705, 714-15 (1984).

A Fourth Amendment search occurs when the government

violates a person's reasonable expectation of privacy. Kyllo, 533

U.S. at 33. The Amendment's protection therefore hinges on whether

the person trying to invoke it can demonstrate they had a

reasonable expectation of privacy in the area searched or item

seized by a government actor. See Carpenter, 585 U.S. at 304. As

we alluded to above, the "reasonable-expectation-of-privacy"

inquiry, commonly referred to as the Katz inquiry, see Katz v.

United States, 389 U.S. 347 (1967), has both a subjective and

objective component. Harper v. Werfel, 118 F.4th 100, 107 (1st

Cir. 2024) (quoting Smith v. Maryland, 442 U.S. 735, 740 (1979)

(citation modified)). A subjective expectation of privacy exists

- 14 -where a person, "by [their] conduct," demonstrates that "[they]

seek[] to preserve something as private." Smith, 442 U.S. at 740.

The objective counterpart of the test is satisfied if the person's

"subjective expectation of privacy is one that society is prepared

to recognize as reasonable." Id. (citation modified). If they

fail to meet either component of the Katz inquiry, the

warrantless-search challenge becomes futile, and our review will

come to a halt.12 See Centeno-González, 989 F.3d at 47 ("There can

only be a Fourth Amendment violation where the complainant had an

expectation of privacy in the item that was searched.").

At this point, the reader might be wondering how our

standard of review impacts the Katz inquiry. Wonder not, though,

for we shall explain. The existence of a person's subjective

expectation of privacy "is a question of fact subject to review

for clear error." United States v. Guzman, 149 F.4th 1132, 1140-41

(10th Cir. 2025) (quoting United States v. Wells, 739 F.3d 511,

522 (10th Cir. 2014)). The question of a person's objective

expectation of privacy lies in the realm of law and is therefore

The question of whether a defendant can successfully

12

demonstrate a reasonable expectation of privacy in the area

searched or item seized has been framed as a question of standing. See United States v. Rheault, 561 F.3d 55, 58 n.8 (1st Cir. 2009). Put plainly, a defendant who fails to sufficiently prove their

expectation of privacy will lack "standing to claim that an illegal search or seizure occurred." United States v. Vilches-Navarrete,

523 F.3d 1, 13 (1st Cir. 2008) (quoting United States v. Mancini,

8 F.3d 104, 107 (1st Cir. 1993)).

- 15 -subject to de novo review. See id.; United States v. Rheault, 561

F.3d 55, 59 n.9 (1st Cir. 2009). Because this threshold "standing"

question is make-or-break for Johnson's appeal, we'll start (and,

as you'll see below, end) here. Let's get into it.

b. Johnson's Reasonable Expectation of Privacy

in His Freenet Activity

Johnson puts forth a number of arguments to justify his

claim of subjective privacy in his Freenet activity. But the

government's response doesn't necessarily oppose Johnson on this

point; it states tersely that the question is, "at best,

debatable." The government urges us (throughout its brief) not to

dwell on the subjective piece but to instead focus on whether

Johnson has proven his claim of objective privacy. Because this

is the most expeditious route to resolving Johnson's Fourth

Amendment claims, we oblige and assume without deciding that

Johnson has satisfied the subjective inquiry of the Katz test. So

the pièce de résistance of our discussion will be determining

whether Johnson adequately justifies his claim of objective

privacy in his Freenet activity.

Of first import is this: It is well established that

"[w]hat a person knowingly exposes to the public, even in his own

home or office, is not a subject of Fourth Amendment protection."

United States v. Morel, 922 F.3d 1, 10 (1st Cir. 2019) (quoting

Katz, 389 U.S. at 351). But what a person "seeks to preserve as

- 16 -private, even in an area accessible to the public, may be

constitutionally protected." Id. To make our determination, we

look at factors such as "ownership, possession and/or control;

historical use of the property searched or the thing seized;

ability to regulate access; the totality of the surrounding

circumstances; . . . and the objective reasonableness of such an

expectancy under the facts of a given case." Id. (quoting United

States v. Stokes, 829 F.3d 47, 53 (1st Cir. 2016)).

To reiterate, Freenet is a peer-to-peer, file-sharing

network that is available at no cost to anyone, anywhere (where

legally permitted) with internet access. This court and all of

our sister circuits that have considered this question hold that

a defendant lacks a reasonable expectation of privacy in content

uploaded to publicly-available, peer-to-peer networks. See Morel,

922 F.3d at 10; United States v. Shipton, 5 F.4th 933, 936 (8th

Cir. 2021) (stating that "a defendant has no objectively reasonable

expectation of privacy in files [they] share[] over a peer-to-peer

network, including those shared anonymously with law enforcement

officers"); United States v. Ewing, 140 F.4th 1339, 1348 (11th

Cir. 2025); United States v. Weast, 811 F.3d 743, 748 (5th Cir.

2016); United States v. Conner, 521 F. App'x 493, 497 (6th Cir.

2013); United States v. Ganoe, 538 F.3d 1117, 1127 (9th Cir. 2008);

United States v. Perrine, 518 F.3d 1196, 1205 (10th Cir. 2008).

- 17 -But Johnson sees things differently. Despite Freenet

being a publicly-accessible, file-sharing network, still, he feels

his claim of an objective expectation of privacy passes muster.

His position goes like this: Because the world is becoming ever so

digital, his "online movements," much like his physical movements,

are likely to reveal his "familial, political, professional,

religious, and sexual associations." Carpenter, 585 U.S. at 311.

Therefore, he asserts, the Fourth Amendment should prohibit law

enforcement from warrantlessly surveilling his online activity.

Unfortunately for Johnson, we must stop him in his tracks. With

this argument, he is misconstruing the scope of the government's

conduct at issue. And as he himself acknowledges, when performing

the Katz inquiry, we must pinpoint "the nature of the state

activity [being] challenged." Smith, 442 U.S. at 741.

The government contends it did not surveil Johnson's

online activity, and, at most, Freenet Roundup captures a user's

activity only at the moment the requestor's solicitation is

transmitted to the government's node. We agree. The government

didn't use Freenet Roundup to surveil the entirety of Johnson's

online movements -- in fact, it didn't necessarily surveil any of

Johnson's online activity. Through Freenet Roundup, the

government functioned like an ordinary Opennet-Freenet user -- by

using its node to receive others' voluntary requests and retrieve

- 18 -data blocks -- and by dint of luck (or unluck), some ended up being

Johnson's.

True, Freenet Roundup did deviate from the ordinary

Freenet software in two material ways. Upon receiving a user's

file request, it used the Hops to Live counter to determine whether

at least 16 hops out of the 18-Hop-maximum remained and, for those

that did, it logged the information transmitted along with the

request.13 The government took additional steps outside the

Freenet-verse to ascertain whether the request was for potentially

illicit content -- and those steps were: (1) comparing the data

blocks' hash values with those in the ICAC's CSAM database,

(2) applying a formula to determine whether the request was from

the originator, and (3) figuring out the subscriber information

for the IP address -- but even taking a conglomerate view of these

steps (as Johnson urges us to do thematically throughout his

briefs), the government's conduct is far short of surveilling

Johnson's online movements. The post-Freenet steps taken by the

government are based solely on the timestamped information that

Johnson transmitted voluntarily when he initiated his requests,

and nothing indicates that the government went beyond that

13While testifying at the suppression hearing, Dr. Levine

agreed that "if [one] were to break up what the law enforcement

node does into two components, one being operation and one being

logging, the logging is what makes the law enforcement node

unique[,] but the operation is the same as any other user."

- 19 -information to access any other local files on his private devices.

See Ewing, 140 F.4th at 1347. The scope of the government's

challenged conduct is therefore limited to its participation on

Freenet as an Opennet user (through its Roundup variant) and its

use of the information that accompanied Johnson's voluntary

requests.

Adamant in his position that his case is on point with

Carpenter, Johnson persists. He says (in essence) that much like

a cell phone, "almost all of daily life involves the internet" so

much so that there's no easy way to avoid using it. And because

the internet is made of "a global network of linked computing

devices," there's no real means to completely privatize one's use

of it (again, his view). Johnson supports his claims by citing

portions of Dr. Levine's hearing testimony wherein he explained

the difficulty of achieving anonymity on the internet. And where

he stated, "[b]y virtue of using the internet, if you expect a

reply, which you always do on the internet [i.e., as Johnson

expected a reply to his CSAM solicitations], just like a letter in

the post office, you have to include your IP address in order to

get a response." Given the reality and necessity of operating in

such a realm, Johnson contends he should maintain a reasonable

expectation of privacy in his internet activity because the

mechanics of its operation make it impossible for him to avoid

some type of identifiable disclosure.

- 20 -We beg to differ for this reason. Johnson argues too

broadly and fails to direct his challenge towards his voluntary

Freenet-specific conduct, as opposed to what he might do or might

have done elsewhere on the internet. Indeed, to argue his claim,

the specific question he must address (as our precedent instructs)

is whether Freenet is so integrated with members of society's, or

even its users', everyday lives that it could provide the

government with an intimate window into their private details.

See, e.g., Harper, 118 F.4th at 109 (assessing whether Coinbase

digital currency exchanges are an indispensable part of daily

life).

In Carpenter, the Supreme Court explained that a person

maintains "a reasonable expectation of privacy in the whole of

their physical movements," which prohibits the government from

warrantlessly collecting one's cell phone location records to

discover their whereabouts. 585 U.S. at 310-11. In making its

narrow decision, the Court reasoned that a cell phone is "almost

a 'feature of human anatomy,'" id. at 311 (quoting Riley v.

California, 573 U.S. 373, 385 (2014)), that "logs a cell-site

record by dint of its operation," id. at 315 (emphasis added).

And "[a]part from disconnecting the phone from the network," said

the Court, "there is no way to avoid leaving behind a trail of

location data." Id. But, in our view, cell phones and their

- 21 -stockpile of location data are patently different from the

technology involved in this case, and here's why.

Unlike cell phones, Freenet is not so intertwined with

its users' lives that it could reveal the "whole of their physical

movements." Id. at 310; see also Pobre, 2022 WL 1136891, at *5

(stating that Freenet "is not a ubiquitous part of everyday life

as is a cell phone"). Far from it. Instead, it is a rarefied,

file-sharing software with limited information on its users'

personal lives (insofar as a user chooses to upload personal

details onto the platform). Freenet does not "follow[] its [users]

beyond public thoroughfares and into private residences, doctor's

offices, political headquarters, and other potentially revealing

locales," Carpenter, 585 U.S. at 311; cf. id.

("[I]ndividuals . . . compulsively carry cell phones with them all

the time."), allowing it to "amass a trail of location data,"

Pobre, 2022 WL 1136891, at *5 (citation modified). Additionally,

Freenet Roundup, as described, is unable to "achieve[] near perfect

surveillance" of a person's physical movements, thereby

categorically excluding it from the "species of technology" that

demands more rigid constitutional scrutiny as did the cell phone

technology involved in Carpenter. 585 U.S. at 318. The law

enforcement tool here simply takes note of bits of information

attached to a user's request -- which is shared and visible to

users on the normal version of Freenet -- and additional

- 22 -investigatory steps (explained above) are required to unveil the

location of the user's node when the request was sent out. This

conduct is in stark contrast to warrantlessly collecting "a

detailed chronicle of a person's physical presence compiled every

day, every moment, over several years" through a person's cell

phone location records. See id. at 315.

Resisting that logic, Johnson argues that we should not

deem his expectation of privacy unreasonable solely because

researchers have created software and come up with a mathematical

formula that allows the government to bypass Freenet's anonymity

and privacy protections. He directs us (once more) to Dr. Levine's

suppression hearing testimony, wherein he stated that his interest

in developing Freenet Roundup was "because law

enforcement . . . found it difficult to conduct investigations" on

that platform. In other words, says Johnson, routine law

enforcement tools would not have allowed the disclosure of his

identity. Continuing, Johnson says in light of Freenet's

assurances that it was better at protecting anonymity than similar

products, notwithstanding Freenet's cautionary warnings about the

risks of being identified when using the platform, it was

reasonable for him to believe that no ordinary Freenet user would

be capable of or even interested in "developing a mathematical

formula, modifying Freenet, and collecting the data necessary" to

reveal the contents of his requested files or of the requestor's

- 23 -origin. And, as Johnson urges, the Fourth Amendment must evolve

to account for these ever-emerging advancements in technology.

Put differently, his claim is that Freenet Roundup amounts to law

enforcement's use of advanced technology to gather information

akin to that which would normally require physically invading a

constitutionally protected area.

Color us unpersuaded. Freenet Roundup does not amount

to exclusive, enhanced technology that provides the government

with a backdoor into a person's private life. Cf. Kyllo, 533 U.S.

at 40 (prohibiting the government from using technology "that is

not in general public use" to learn the private details of a

person's home). Freenet Roundup works only to "facilitate[] [the

government's] membership into Freenet and record[] the file

requests that the [government node] receives." Pobre, 2022 WL

1136891, at *6. Aside from logging and filtering information that

accompanies each request voluntarily sent to other Freenet users,

as we've discussed, Freenet Roundup otherwise operates like a

normal user on the platform. These actions therefore could not

fairly be viewed as conduct involving technology that "is not in

general public use." Kyllo, 533 U.S. at 34; see Ewing, 140 F.4th

at 1349 (stating law enforcement used "Torrential Downpour" to

"merely scan[] publicly available information . . . not shrink the

realm of guaranteed privacy by exposing information that was not

already broadcast to the public" (citation modified)).

- 24 -Johnson's mention of the government's purportedly

sophisticated hash value cataloguing and application of its

mathematical formula does not change our minds. Dr. Levine

testified that he used "standard techniques" and that he "didn't

invent some crazy math to" design the formula. And as described,

it uses only the information transmitted as part of the user's

request -- such as the number of immediate peers a Freenet user

has and the remaining number of Hops for each request it logs -- to

calculate the likelihood that the request came from the originator.

Nothing on the record suggests to us that this conduct is so

advanced and out of reach, especially when Freenet itself warned

that users with "moderate resources" could ascertain similar

information. Further, once Johnson voluntarily sent out his

request, he could neither reasonably expect the information to

remain private nor control how strangers would use the information,

which applies equally when the government lawfully obtains

potentially incriminating information. Compare Boroian v.

Mueller, 616 F.3d 60, 67 (1st Cir. 2010) (noting that courts have

held "the government's matching of a lawfully obtained

identification record against other records in its lawful

possession does not infringe on an individual's legitimate

expectation of privacy"), with Carpenter, 585 U.S. at 314 (stating

that, under the third-party doctrine, "an individual has a reduced

expectation of privacy in information knowingly shared with

- 25 -another"). Thus, the government's use of information Johnson

voluntarily disseminated on Freenet does not alter our conclusion.

See United States v. Jacobsen, 466 U.S. 109, 117 (1984) ("Once

frustration of the original expectation of privacy occurs, the

Fourth Amendment does not prohibit governmental use of the

now-nonprivate information.").

The government posits that by using Freenet Roundup to

receive requests Johnson voluntarily sent to strangers on Freenet,

its actions are more akin to that of an undercover officer invited

to participate in an illicit transaction. See Lewis v. United

States, 385 U.S. 206, 210-11 (1966). But Johnson pushes back on

such a comparison and says it is inapt. He suggests that, unlike

being chatty with an undercover, he "relied on the

privacy-protection" afforded by Freenet, "not on his confidence in

other Freenet users." Johnson argues that he didn't announce to

anyone on Freenet (or otherwise) that he sought to download CSAM,

and, normally, the users receiving his requests have no idea of

the contents of any particular block or file. Thus, society should

see his expectation of privacy as reasonable.

We remain unconvinced by Johnson's argument and instead,

our view tracks that of the government's. Similar to inviting an

"undercover agent to [their] home for the specific purpose of

executing a felonious sale of narcotics," id. at 210, Johnson

voluntarily connected his computer to strangers on Freenet to

- 26 -retrieve files. Even when warned throughout his time on the

platform, Johnson never opted to toggle on Freenet's

more-privatized Darknet mode.14 And the government never targeted

Johnson specifically, nor did it ever solicit his Freenet requests.

What law enforcement did do was go on Freenet as an Opennet-user

(something Johnson does not argue was improper governmental

conduct in and of itself), and that is what caused it to receive

peers' requests, including the illicit ones Johnson initiated.

See Pobre, 2022 WL 1136891, at *6 ("From this, the [c]ourt cannot

conclude that the technology did anything more than receive that

which Pobre and others willingly shared in Freenet."). Such

conduct does not violate the Fourth Amendment.

Johnson won't budge. He says Freenet's warnings don't

defeat his privacy claims because they signal only that a user's

identity could be discovered, not that they could be made out as

the original requestor of a file or that the contents of a

requested file could be revealed. He's wrong. Freenet warned

Johnson -- like all users operating in Opennet mode -- that his IP

address was vulnerable to identification, that "an attacker with

moderate resources may be able to trace [his] activity on Freenet

back to [him,]" and that "[i]t may be quite easy for others to

14To be clear, we are not saying that a Freenet user operating

in Darknet mode would have a reasonable expectation of privacy in

their activity on the platform. We leave that question for another day.

- 27 -discover [his] identity." He was therefore adequately warned that

he was opening his Freenet transmissions to the world, including

the world of the government. See Ganoe, 538 F.3d at 1127. And

despite any purported ambiguity in the warnings, Johnson was at

least on notice that his activity could be traced back to him.

What's more, by continuing to use Freenet in Opennet mode after

the warnings were displayed, Johnson failed to take any

"affirmative steps to protect the [files]" by switching to Darknet

mode. Morel, 922 F.3d at 10. He presents to us no case, and we

are aware of none, that suggests society would deem his expectation

of privacy reasonable because he believed only some aspects of his

identity were discoverable.

Finally, Johnson asserts that Freenet is materially

different from other peer-to-peer networks, and therefore, any

cases involving those other platforms are inapplicable. As opposed

to traditional networks in which users open their computers and

files to the public, he contends that Freenet's users can only

access encrypted data blocks that are unidentifiable without a

manifest key. Johnson says these files are not made public in a

way that would call into question a Freenet user's expectation of

privacy.

Again, we disagree. Despite his many claims that he

used Freenet to anonymize his file-sharing activity to the furthest

extent possible, (to repeat) Johnson voluntarily operated on

- 28 -Freenet in low security Opennet mode when transmitting his requests

after being explicitly warned of that mode's shortcomings. Because

of his personal choice to connect with total strangers on Freenet,

we see no meaningful difference between Freenet and other

peer-to-peer, file-sharing networks. Once he chose to connect

openly in the Freenet-verse, "his expectation of privacy ha[d]

already been frustrated." Ewing, 140 F.4th at 1348 (citation

modified). And "[o]nce frustration of the original expectation of

privacy occurs, the Fourth Amendment does not prohibit

governmental use of the now nonprivate information." Id.

(alteration in original) (quoting Jacobsen, 466 U.S. at 117).

Against all of this, Johnson has failed to prove a

reasonable expectation of privacy in his Freenet activity, and we

needn't inquire any further. See United States v. Mayendía-Blanco,

905 F.3d 26, 37 (1st Cir. 2018) (stating that "[t]he simplest way

to decide a case is often the best" (alteration in original)

(quoting Stor/Gard, Inc. v. Strathmore Ins., 717 F.3d 242, 248

(1st Cir. 2013))).

V. Conclusion

Johnson's challenge to the district court's denial of

his suppression motion is unsuccessful. The matter is thus

affirmed.

- 29 -