                This opinion is subject to revision before final
                     publication in the Pacific Reporter

                                2015 UT 24

                                   IN THE

      S UPREME C OURT OF THE S TATE OF U TAH
                             STATE OF UTAH ,
                                Appellee,
                                      v.
                            DANIEL ROBERTS,
                              Appellant.

                            No. 20120884
                        Filed January 30, 2015

                   Seventh District, Castle Dale
                The Honorable Douglas B. Thomas
                         No. 101700043

                                Attorneys:
   Sean D. Reyes, Att’y Gen., Marian Decker, Asst. Att’y Gen.,
                   Salt Lake City, for appellee
               Sean P. Hullinger, Lehi, for appellant

   JUSTICE PARRISH authored the opinion of the Court, in which
    CHIEF JUSTICE DURRANT, ASSOCIATE CHIEF JUSTICE NEHRING ,
             JUSTICE DURHAM , and JUSTICE LEE joined.


   JUSTICE PARRISH , opinion of the Court:

                          INTRODUCTION
    ¶1 Daniel Roberts entered a conditional guilty plea to five
charges of sexual exploitation of a minor arising from child
pornography on his laptop computer. On appeal, Mr. Roberts
challenges four of the district court’s pretrial rulings. He first
challenges the propriety of law enforcement’s use of the Wyoming
Toolkit, a computer program and database used to identify child
pornography shared over the Internet through peer-to-peer file
sharing networks. Mr. Roberts next challenges the district court’s
ruling that denied him discovery of the Wyoming Toolkit. He also
brings a constitutional challenge to Utah’s sexual exploitation of a
minor statute (Sexual Exploitation Statute) under which he was
charged, Utah Code section 76-5a-3 (2009) (renumbered as Utah
Code section 76-5b-201). Finally, Mr. Roberts challenges the district
                         STATE v. ROBERTS
                       Opinion of the Court

court’s denial of his motion in limine to exclude all evidence
obtained by or related to the Wyoming Toolkit. We affirm the
district court on all issues.
                         BACKGROUND
    ¶2 Utah’s Internet Crimes Against Children task force (ICAC)
works to prevent the online distribution of child pornography. The
ICAC searches peer-to-peer (P2P) file sharing networks for child
pornography being shared among P2P users. Gnutella, one such P2P
network, allows its users to share digital files directly over the
Internet.1 Gnutella uses what is called the secure hash algorithm
(SHA-1) encryption method to assign a unique digital signature to
each file shared over its network. Because each digital file has a
different SHA-1 value, those values can be used to identify a file.
Through prior investigations, law enforcement has compiled a
database of thousands of SHA-1 values that correspond to files
containing child pornography. This database, along with software
that searches Gnutella for the identified SHA-1 values, is known as
the Wyoming Toolkit.
    ¶3 The ICAC uses the Wyoming Toolkit to monitor Gnutella
for IP addresses sharing files with suspect SHA-1 values. Once the
Toolkit flags an IP address sharing a file with an SHA-1 value that
matches known child pornography files, officers confirm that the
suspect file is indeed child pornography either by downloading and
viewing the file directly or by comparing the identified file’s SHA-1
value with SHA-1 values of known child pornography contained in
databases like the National Child Victim Identification Program.
Upon confirming that the identified file is child pornography,
officers send an administrative subpoena to the applicable internet
service provider to obtain the subscription information associated
with the identified IP address.
    ¶4 During a 2009 investigation, the ICAC determined that an
IP address in Emery County, Utah, had used Gnutella to share
hundreds of “files with SHA-1 digital signatures identical to images
of suspected child pornography” during a five month period. The
ICAC submitted these findings to FBI Agent Sonja Nordstrom. Upon




   1
     For additional information on Gnutella, see Definition of:
Gnutella, PCMAG.COM , http://www.pcmag.com/encyclopedia/term
/43835/gnutella (last visited Jan. 20, 2015).

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                       Opinion of the Court

confirming the files contained child pornography,2 Agent Nordstrom
served a subpoena on Emery Telecom, the local internet service
provider, which was able to identify Mr. Roberts as the owner of the
suspect IP address. Based on this information, Agent Nordstrom
obtained a search warrant for Mr. Roberts’ home and computers.
    ¶5 Mr. Roberts was not home the day police officers executed
the search warrant. Agent Nordstrom called Mr. Roberts on his cell
phone to inform him of the search, but did not discuss the purpose
of the investigation. Mr. Roberts told Agent Nordstrom that he was
in Ogden, Utah, where his wife was in the hospital. Agent
Nordstrom later spoke with Mr. Roberts’ wife, who indicated that
Mr. Roberts had his laptop computer with him in Ogden.
    ¶6 Agent Nordstrom traveled to Ogden to meet with
Mr. Roberts. Mr. Roberts brought his laptop to the meeting, and
Agent Nordstrom explained to Mr. Roberts that he was being
investigated for possession of child pornography. After some
questioning, Mr. Roberts admitted that he had been downloading
child pornography for approximately a year and that he had been in
the process of deleting the child pornography from his computer
since Agent Nordstrom had called him. After Mr. Roberts made this
admission, Agent Nordstrom asked if she could see his laptop.
Mr. Roberts consented. Agent Nordstrom subsequently obtained a
search warrant specifically for Mr. Roberts’ laptop.
    ¶7 Mr. Roberts’ laptop was taken to a computer forensic lab,
where an examiner found video and still images of child
pornography. Mr. Roberts was charged with thirty counts of sexual
exploitation of a minor, a second degree felony. UTAH CODE § 76-5a-
3 (2009).3 Before trial, Mr. Roberts made four motions that are the
subject of this appeal. First, he moved to suppress the evidence of
child pornography found on his laptop. Relying on the United States
Supreme Court case Kyllo v. United States, 533 U.S. 27 (2001),
Mr. Roberts argued that the Wyoming Toolkit, like the thermal


   2
     To confirm the content of these files, Agent Nordstrom
compared the SHA-1 values of the files shared by Mr. Roberts with
the SHA-1 values of files she had previously viewed that contained
child pornography.
   3
     In 2011, the Legislature renumbered section 76-5a-3 as 76-5b-201
and made minor change to its substance. Because Mr. Roberts was
charged prior to this amendment, we rely on the May 2009 version
for purposes of his appeal.

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                        Opinion of the Court

image scanning at issue in Kyllo, constituted a search, and therefore
use of the Toolkit without a warrant violated the Fourth
Amendment to the United States Constitution. Mr. Roberts further
argued that he had an expectation of privacy in the contents of his
computer and that by accessing those contents through the
Wyoming Toolkit, the State violated his expectation of privacy
through an unlawful search. The district court denied Mr. Roberts’
motion, reasoning that the Wyoming Toolkit did not have “the same
intrusiveness as thermal imaging” and that “peer-to-peer file sharing
is not entitled to a reasonable expectation of privacy.”
    ¶8 Second, Mr. Roberts moved to compel discovery of the
Wyoming Toolkit and its methodologies. He also moved to compel
discovery of “any and all associated program documentation,
instruction manuals, technical support materials, training materials,
and purchase documents . . . to verify that the images [he] is alleged
to have possessed are in fact[] illegal images.” The district court
granted the motion in part and denied it in part. It held that
Mr. Roberts was entitled to discovery of “whatever information the
State has in regards to this case,” including “any information the
State has” regarding the SHA-1 values associated with the files
found on Mr. Roberts’ laptop. But it denied Mr. Roberts’ motion to
compel discovery of every SHA-1 value in the Wyoming Toolkit
database and “the search algorithm process and methodology
utilized” in the Toolkit. It reasoned that discovery of the Toolkit was
unnecessary for the purpose Mr. Roberts alleged because Agent
Nordstrom had personally verified that the files Mr. Roberts had
shared on Gnutella were indeed child pornography and because
“disclosure of investigative techniques and procedures would
interfere with law enforcement efforts.”
    ¶9 Third, Mr. Roberts moved to dismiss the case on the ground
that Utah’s Sexual Exploitation Statute is unconstitutional.
Mr. Roberts argued that the statute violates the Uniform Operation
of Laws Provision of the Utah Constitution on its face because it
unconstitutionally distinguishes between (1) individuals who
illegally possess child pornography and (2) individuals who may
legally possess child pornography such as law enforcement officers
acting within the scope of a criminal investigation and employees or
agents of entities that report and prevent child pornography when
they are acting in good faith and within the scope of their




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employment.4 Mr. Roberts also argued that, as applied, the statute
discriminates between prosecuting attorneys and defense attorneys
who may come into possession of child pornography during their
representation or prosecution of a defendant charged under the
Sexual Exploitation Statute. Mr. Roberts asserted that defense
attorneys, but not prosecuting attorneys, who come into possession
of child pornography would be in violation of the statute.
    ¶10 The district court denied Mr. Roberts’ motion to dismiss,
holding that the Sexual Exploitation Statute was not
unconstitutional. Although the statute creates distinct classifications
between those who may and may not legally possess child
pornography, the district court reasoned that those classifications do
not “impose any disparate treatment on persons similarly situated.”
(Citing State v. Robinson, 2011 UT 30, 254 P.3d 183).


   4
   The relevant language of Utah Code section 76-5a-3, effective
May 2009, is as follows:
       (1) A person is guilty of sexual exploitation of a minor:
           (a) when the person:
               (i) knowingly produces, possesses, or possesses
       with intent to distribute child pornography; or
       (ii) intentionally distributes or views child
       pornography;
       ....
       (5) This section may not be construed to impose
       criminal or civil liability on:
           (a) any entity or an employee, director, officer, or
       agent of an entity when acting within the scope of
       employment, for the good faith performance of:
               (i) reporting or data preservation duties
       required under any federal or state law; or
               (ii) implementing a policy of attempting to
       prevent the presence of child pornography on any
       tangible or intangible property, or of detecting and
       reporting the presence of child pornography on the
       property; or
           (b) any law enforcement officer acting within the
       scope of a criminal investigation.


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                        Opinion of the Court

    ¶11 The district court also rejected Mr. Roberts’ as-applied
challenge to the statute. While it acknowledged that defense
attorneys and prosecutors are similarly situated and that the statute
discriminates between them, it concluded that the distinction is
justified by a legitimate government interest in eliminating the
market for child pornography. It also observed that law enforcement
allows defense attorneys to view evidence of child pornography as
part of their representation, if they do so at the Regional Computer
Forensics Lab (RCFL). It therefore held that although prosecutors
and defense attorneys are treated differently under the statute, the
restriction on defense attorneys is not overly burdensome, is
reasonable, and is justified by the State’s interest in eliminating the
dissemination of child pornography.
    ¶12 Finally, Mr. Roberts filed a motion in limine to preclude the
State from offering expert testimony on the Wyoming Toolkit. He
argued that the admission of evidence regarding “the technical
elements of the Wyoming Toolkit, the scientific principles that
underlie the technology, or the reliability of the inputs required by
the system” would be impermissible under the Utah Rules of
Evidence because “[t]he reliability of the methods has not been
demonstrated by the State, nor has the defense had opportunity to
challenge them.”
    ¶13 The district court held an evidentiary hearing on
Mr. Roberts’ motion to exclude expert testimony, during which the
State presented the testimony of Special Agent Coy Acocks, an
expert on the Wyoming Toolkit. Agent Acocks testified as to the
methodologies of the Toolkit, explaining that the technology used to
develop the Toolkit is publicly available and could be used by
anyone to search P2P networks. He also testified that the Toolkit
correctly identifies child pornography files with extraordinarily high
accuracy. Agent Acocks explained that officers using the Toolkit do
not rely on the Toolkit alone to obtain a warrant to search a
suspected computer. Rather, they conduct further investigation by
reviewing files that the Toolkit has identified as child pornography
to confirm the Toolkit’s accuracy. Mr. Roberts presented no
competing expert testimony or other evidence challenging Agent
Acocks’ testimony.
   ¶14 At the conclusion of the hearing, the district court ruled
from the bench that the Wyoming Toolkit employed reliable
methods based on “fairly common and available standard
processes.” The court found that the officers using the Toolkit are
well trained, that the SHA-1 values’ reported accuracy is reliable,

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                        Opinion of the Court

and that the process used to ascertain IP addresses is reliable. The
court also found that the Toolkit “is simply a tool to be used by law
enforcement officers as one step in the investigation of a case. It is
not the conclusion.” Once officers use the Toolkit to identify possible
child pornography, they undertake additional steps to assure that
the files identified by the Toolkit and associated with a certain IP
address are actually child pornography. The court thus concluded
that the Wyoming Toolkit was a reliable basis for expert testimony.
    ¶15 Mr. Roberts entered a plea agreement with the State under
which he pled conditionally guilty to five counts of sexual
exploitation of a minor. The State dismissed the remaining twenty-
five counts. The district court subsequently sentenced Mr. Roberts
to concurrent prison terms of one-to-fifteen years, but suspended the
prison terms and placed Mr. Roberts on 36 months of probation,
including 240 days in the county jail. Mr. Roberts timely appealed
his conviction to the court of appeals, which certified his appeal to
this court. He challenges each of the pretrial rulings identified above.
We have jurisdiction under Utah Code section 78A-3-102(3)(b).
                    STANDARDS OF REVIEW
    ¶16 Different standards of review apply to each of Mr. Roberts’
arguments. We review for correctness the district court’s denial of
Mr. Roberts’ motion to suppress on the ground that law
enforcement’s use of the Wyoming Toolkit constituted an unlawful
search. State v. Tripp, 2010 UT 9, ¶ 23, 227 P.3d 1251. Because district
courts “have broad discretion in matters of discovery,” we review
for an abuse of discretion the district court’s ruling that denied
Mr. Roberts discovery of the Wyoming Toolkit. Green v. Louder,
2001 UT 62, ¶ 37, 29 P.3d 638. Mr. Roberts’ constitutional challenge
to the Sexual Exploitation Statute presents a question of law that we
review for correctness, recognizing that “all statutes are presumed
to be constitutional and the party challenging a statute bears the
burden of proving its invalidity.” State v. Angilau, 2011 UT 3, ¶ 7,
245 P.3d 745 (internal quotation marks omitted). Finally, because
district courts “have considerable discretion in determining the
admissibility of expert testimony,” we review Mr. Roberts’ challenge
to the expert testimony regarding the Wyoming Toolkit for an abuse
of discretion. State v. Butterfield, 2001 UT 59, ¶ 28, 27 P.3d 1133.
                             ANALYSIS
 I. MR. ROBERTS’ ARGUMENTS ARE ADEQUATELY BRIEFED
   ¶17 As a preliminary matter, we address the State’s contention
that Mr. Roberts’ arguments are inadequately briefed. The State

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                        Opinion of the Court

argues that Mr. Roberts’ appellate brief “is filled with conclusory
assertions and virtually bereft of citations to the record” and
“provides no meaningful analysis” of the district court’s rulings. The
State thus asks us to dismiss each of Mr. Roberts’ arguments as
inadequately briefed.
    ¶18 Rule 24 of the Utah Rules of Appellate Procedure
“prescribe[s] standards for the form, organization, and content of a
brief on appeal.” State v. Nielsen, 2014 UT 10, ¶ 33, 326 P.3d 645. Rule
24 requires that the arguments “contain the contentions and reasons
of the appellant with respect to the issues presented . . . with
citations to the authorities, statutes, and parts of the record relied
on.” UTAH R. APP. P. 24(a)(9). This standard for adequate briefing is
a subjective standard, and determining compliance is left to the
discretion of the appellate court. Nielsen, 2014 UT 10, ¶ 34. In
exercising this discretion, we assess the adequacy of a brief “not as
a matter of gauging procedural compliance with the rule, but as a
necessary component of our evaluation of the case on its merits.” Id.
While we may exercise our discretion to disregard or strike briefs
that do not comply with rule 24’s substantive requirements,
UTAH R. APP. P. 24(k), we are not required to do so. See State v.
Thomas, 961 P.2d 299, 305 (Utah 1998) (explaining that “failure to cite
to pertinent authority may not always render an issue inadequately
briefed”). Therefore, like the marshaling requirement imposed by
rule 24(a)(9) of the Rules of Appellate Procedure, our adequate
briefing requirement is not a “hard-and-fast default notion.” Nielsen,
2014 UT 10, ¶ 40. Instead, it is a “natural extension of an appellant’s
burden of persuasion.” Id. ¶ 41. As a result, appellants who fail to
follow rule 24’s substantive requirements will likely fail to persuade
the court of the validity of their position.
    ¶19 Despite the discretionary nature of our briefing
requirements, we have seen an increasing number of appellees who
spend considerable time arguing over the adequacy of the
appellant’s brief, rather than addressing the merits of the appellant’s
position. In taking such an approach, appellees are often guilty of the
very deficiency of which they complain. Although the briefing
standard articulated in rule 24(a) is directed in the first instance to
appellants, rule 24(b) applies those same requirements to the brief of
the appellee. Broderick v. Apartment Mgmt. Consultants, L.L.C.,
2012 UT 17, ¶ 10, 279 P.3d 391. As a result, an appellee who argues
only that the appellant has inadequately briefed issues will likely fail
to submit a brief that “contain[s] the contentions and reasons of the
appellee with respect to the issues presented in the opposing brief.”

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                        Opinion of the Court

Brown v. Glover, 2000 UT 89, ¶ 22, 16 P.3d 540. Appellees who rely
solely on inadequate briefing arguments therefore assume a
considerable risk of defaulting on appeal.
    ¶20 In this case, although the State’s initial brief addressed the
merits of some of Mr. Roberts’ claims, it did not address the merits
of two of his claims. Instead, it argued only that those claims had
been inadequately briefed. In so doing, the State took the risk that
we would disagree with its assessment of the adequacy of
Mr. Roberts’ briefing and thereby forfeit its chance to respond to the
merits of those two claims. While we could have defaulted the State
for its failure to argue the substance of the issues, we exercised our
discretion to provide the State with an opportunity to supplement its
brief. We caution, however, that an appellee who fails to respond to
the merits of an appellant’s argument will risk default. Rather than
challenging the adequacy of an appellant’s brief, an appellee should
instead layout the relevant legal standard and point out why the
appellant has failed to carry his burden of persuasion.
    ¶21 Having clarified the standard for adequate briefing, we
conclude that most of Mr. Roberts’ arguments are adequately
briefed. Although Mr. Roberts’ arguments are in some instances
poorly articulated and weakly supported by legal authority, his
briefing does not fall below the requirements of rule 24. Unlike cases
where the appellant “failed to cite any case law from any jurisdiction
in order to set forth the elements of, or the legal standards for, his
claims,” Carlton v. Brown, 2014 UT 6, ¶ 20, 323 P.3d 571, Mr. Roberts
has generally cited to legal authority to support his arguments. And
while his citations to the record are sparse, he has, for the most part,
directed this court to the relevant motions, memoranda, and district
court rulings that are the subject of his appeal.
    ¶22 In summary, Mr. Roberts has adequately briefed most of his
arguments. That some of his arguments are not well organized or
persuasive does not necessarily mean they are inadequately briefed.
Instead, it suggests that Mr. Roberts has not satisfied his burden of
persuasion on appeal.5


   5
    We do, however, agree with the State as to the inadequacy of
Mr. Roberts’ arguments that the district court erred in denying his
motion to clarify its ruling on the discovery of the Wyoming Toolkit.
Although Mr. Roberts asserts error, he does not direct us to any
place in the record where the district court made a ruling on this
                                                        (continued...)

                                   9
                          STATE v. ROBERTS
                        Opinion of the Court

       II. THE DISTRICT COURT DID NOT ERR IN DENYING
               MR. ROBERTS’ MOTION TO SUPPRESS
    ¶23 Mr. Roberts argues that the district court erred in denying
his motion to suppress the evidence of child pornography found on
his computer under the theory that law enforcement’s use of the
Wyoming Toolkit constituted an illegal search. According to
Mr. Roberts, the warrant that the State obtained to search his
computer was based on an unlawful search of the files Mr. Roberts
shared on Gnutella. He argues that the evidence obtained from that
search therefore should have been suppressed. He also argues that
the administrative subpoena issued to Emery Telecom was
improper. We disagree. Law enforcement’s use of the Wyoming
Toolkit to identify files freely shared on P2P networks does not
constitute a search. And the Emery Telecom subpoena was
procedurally sound under the law as it existed at the time it was
issued.
 A. Use of the Wyoming Toolkit to Identify Child Pornography in a File
            Shared Openly on a P2P Network Is Not a Search
    ¶24 The Fourth Amendment to the United States Constitution
prohibits “unreasonable searches and seizures.” Government
conduct that infringes upon a subjective and “reasonable expectation
of privacy” constitutes a search and therefore cannot take place
absent a valid warrant or a recognized exception to the warrant
requirement. State v. Price, 2012 UT 7, ¶ 9, 270 P.3d 527 (internal
quotation marks omitted). A subjective and reasonable expectation
of privacy exists when “(1) an individual has ‘exhibited an actual
(subjective) expectation of privacy’ and (2) ‘the expectation [is] one
that society is prepared to recognize as reasonable.’” Id. (alteration
in original) (quoting Katz v. United States, 389 U.S. 347, 361 (1967)
(Harlan, J., concurring)). In this case, we must decide whether
Mr. Roberts had a subjective expectation of privacy in files he shared
on Gnutella and, if so, whether that expectation of privacy was
objectively reasonable.



   5
    (...continued)
issue, nor does he explain the district court’s basis for denying the
motion. Indeed, Mr. Roberts failed to request the transcript of the
hearing in which the court heard argument on this issue. As a result,
we have no basis on which to review the district court’s ruling on the
discoverability of the Wyoming Toolkit.

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                        Opinion of the Court

    ¶25 Although we have yet to consider whether a reasonable
expectation of privacy exists in a file shared over a P2P network,
several federal courts have considered the issue and none has found
an expectation of privacy. See United States v. Hill, 750 F.3d 982, 986
(8th Cir. 2014) (“[A] defendant has no reasonable expectation of
privacy in files . . . retrieved from his personal computer where [the
defendant] admittedly installed and used LimeWire to make his files
accessible to others for file sharing.” (second and third alterations in
original) (internal quotation marks omitted)); United States v. Conner,
521 F. App’x 493, 497 (6th Cir. 2013) (finding no reasonable
expectation of privacy in files shared through a P2P file-sharing
program); United States v. Norman, 448 F. App’x 895, 897
(11th Cir. 2011) (same); United States v. Borowy, 595 F.3d 1045,
1047–48 (9th Cir. 2010) (same); United States v. Perrine, 518 F.3d 1196,
1205 (10th Cir. 2008) (same). We agree with this federal precedent
and hold that there is no reasonable expectation of privacy in a file
that an individual publicly shares on a P2P network.
    ¶26 In this case, Mr. Roberts publicly shared his files on
Gnutella, thereby rendering them publicly available to anyone with
a Gnutella client. And because Mr. Roberts made no effort to limit
access to his files on Gnutella, he exhibited no subjective expectation
of privacy in those files. Neither the ICAC’s investigation of Mr.
Roberts’ publicly shared files nor its use of the Wyoming Toolkit to
identify the files as child pornography constituted a search. The
Wyoming Toolkit merely enabled the ICAC officers to recognize files
with SHA-1 values associated with child pornography. But it did not
allow the government to access private information on Mr. Roberts’
computer. It therefore did not invade a constitutionally protected
private space.
    ¶27 Without acknowledging the federal case law undermining
his argument, Mr. Roberts relies on the United States Supreme
Court’s opinion in Kyllo v. United States, 533 U.S. 27 (2001). In Kyllo,
the Court held that the use of thermal imaging scanners to detect
high-intensity lamps used to grow marijuana in a home constituted
an unlawful search. Id. at 40. The Court reasoned that the thermal
imaging intruded on the interior of the home, which is protected by
a high expectation of privacy. Id. The Court thus held that where
“the Government uses a device that is not in general public use, to
explore details of the home that would previously have been
unknowable without physical intrusion, the surveillance is a ‘search’
and is presumptively unreasonable without a warrant.” Id.



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                          STATE v. ROBERTS
                        Opinion of the Court

    ¶28 Mr. Roberts focuses on the fact that the government in Kyllo
used technology that is not publicly available. He argues that, like
the thermal imaging scanners at issue in Kyllo, the Wyoming Toolkit
is not accessible to the public. But the greater concern in Kyllo was
that the government was using the technology to intrude the privacy
of the home. The Wyoming Toolkit, on the other hand, is used only
to identify child pornography in files that are publicly shared on
P2P network. Unlike thermal imaging scanners, the Toolkit does not
intrude on any interest in which the defendant has a reasonable
expectation of privacy. Use of the Toolkit therefore does not
constitute an unlawful search.
   B. A Search Did Not Take Place When Law Enforcement Obtained
       Mr. Roberts’ Subscription Information from His Internet
                          Service Provider
    ¶29 In addition to challenging the government’s use of the
Wyoming Toolkit, Mr. Roberts argues that the government
conducted an unconstitutional search when it used his IP address to
identify him through the Emery Telcom subpoena. But Mr. Roberts
once again ignores the overwhelming weight of authority finding no
reasonable expectation of privacy in subscription information, like
an IP address, given to an internet service provider. See Perrine, 518
F.3d at 1204 (”Every federal court to address this issue has held that
subscriber information provided to an internet provider is not
protected by the Fourth Amendment’s privacy expectation.”).
    ¶30 Although Mr. Roberts points to no case law in support of
his position, he relies on two recently enacted statutes that he argues
are relevant to the propriety of the Emery Telecom subpoena. The
first, Senate Bill 46, which became effective on March 25, 2014,
amends the administrative subpoena statute to require the signature
of a judge rather than a prosecutor for all administrative subpoenas.
2014 Utah Laws 254–55 (ch. 47); see also UTAH CODE § 77-22-2.5. The
second, House Bill 128, which became effective on July 1, 2014,
added provisions to the Utah Code that now require law
enforcement to obtain a warrant to search for the location
information of an electronic device. 2014 Utah Laws 942–43 (ch. 223);
see also UTAH CODE § 77-23c-101 to -103.
    ¶31 Mr. Roberts relies on our per curiam decision in
State v. Belgard, 615 P.2d 1274, 1276 (1980), to argue that these
statutory amendments apply retroactively to his case and that the
administrative subpoena issued to Emery Telecom in 2009 was
procedurally deficient. In Belgard, this court, quoting the Seventh


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                        Opinion of the Court

Circuit, stated:
       It is well established that when a lower court relies on
       a legal principle which is changed by treaty, statute, or
       decision prior to direct review, an appellate court must
       apply the current law rather than the law as it existed
       at the time the lower court acted. ‘Intervening and
       conflicting decisions will thus cause the reversal of
       judgments which were correct when entered.’
Id. (quoting United States v. Fitzgerald, 545 F.2d 578, 581
(7th Cir. 1976)). When viewed in isolation, the Fitzgerald and Belgard
line of cases appears to support the retroactive application of these
statutes. But the United States Supreme Court has clarified that this
rule is inapplicable where the legislature has expressed its intent that
a statute not be applied retroactively. Kaiser Aluminum & Chem. Corp.
v. Bonjorno, 494 U.S. 827, 837–38 (1990) (explaining that, in the
context of retroactivity, “where [legislative] intent is clear, it
governs”).
     ¶32 In Utah, the Legislature has expressed a clear presumption
against retroactive application. UTAH CODE § 68-3-3 (“A provision of
the Utah Code is not retroactive, unless the provision is expressly
declared to be retroactive.”). As a result, we generally “apply the law
as it exists at the time of the event regulated by the law in question.”
State v. Clark, 2011 UT 23, ¶ 13, 251 P.3d 829. Because the intent of
the Legislature is clear in this regard, we repudiate our Belgard
decision insofar as it purportedly expresses a presumption in favor
of retroactive application.
     ¶33 In this case, neither statute on which Mr. Roberts relies
declares that it applies retroactively. We therefore apply the law as
it existed at the time of the relevant event, which in this case was the
State’s issuance of the administrative subpoena Emery Telecom in
October 2009. At that time, Utah Code section 77-22-2.5(2) permitted
prosecutors to issue administrative subpoenas, and the Utah Code
did not require a warrant to search an electronic device’s location
information. Because the Emery Telecom subpoena was issued in
compliance with the law at the time, we reject Mr. Roberts’ challenge
to its validity.
   ¶34 In summary, we hold that the government’s use of the
Wyoming Toolkit to identify child pornography in files shared on a
P2P network does not constitute a search. And under the law that
was in place at the time, a search did not take place when law
enforcement obtained Mr. Roberts’ subscription information through

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                        Opinion of the Court

the subpoena to Emery Telecom. We therefore affirm the district
court’s denial of Mr. Roberts’ motion to suppress.
 III. THE DISTRICT COURT DID NOT ABUSE ITS DISCRETION
       IN DENYING MR. ROBERTS’ MOTION TO COMPEL
           DISCOVERY OF THE WYOMING TOOLKIT
    ¶35 Mr. Roberts argues that the district court abused its
discretion in denying his motion to compel discovery of the
Wyoming Toolkit, including its methodologies and all of the SHA-1
values in its database. We review this claim for an abuse of
discretion and the appellant bears a heavy burden in showing that
the district court abused its discretion. R & R Energies v. Mother Earth
Indus., Inc., 936 P.2d 1068, 1079 (Utah 1997). To meet this burden, the
appellant must show either “an erroneous conclusion of law or [that]
there is no evidentiary basis” for the district court’s discovery ruling.
Id. (internal quotation marks omitted). Mr. Roberts has shown
neither.
    ¶36 In ruling on the motion to compel, the district court allowed
Mr. Roberts to discover any information the State had regarding his
case, including the SHA-1 values associated with files found on his
laptop. But the district court denied the remainder of Mr. Roberts’
discovery request for two independent reasons: (1) that discovery of
the Toolkit would not produce the evidence Mr. Roberts sought (i.e.,
verification that the files Mr. Roberts had shared and that the Toolkit
had detected were indeed child pornography) and (2) that disclosure
of all of the Toolkit’s methodologies and SHA-1 values would harm
future ICAC investigations.
    ¶37 Mr. Roberts’ main argument on appeal is that the Toolkit
and its methodologies are not privileged. But the district court did
not hold that the Toolkit was privileged information; it merely held
that discovery of all aspects of the Toolkit and its methodologies
were not relevant and would be harmful to future ICAC
investigations. And because Mr. Roberts provides no authority to the
contrary, he has failed to show that the district court abused its
discretion by denying discovery.
    ¶38 Moreover, Mr. Roberts does not address the district court’s
alternative ground for denying the motion: that discovery of the
Toolkit would not be useful in verifying that the files Mr. Roberts
had shared on Gnutella contained child pornography. See Salt Lake
Cnty. v. Butler, Crockett & Walsh Dev. Corp., 2013 UT App 30, ¶ 28,
297 P.3d 38 (explaining that an appellate court “will not reverse a
ruling of the trial court that rests on independent alternative

                                   14
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                        Opinion of the Court

grounds where the appellant challenges only one of those grounds”).
As the district court reasoned, discovery of all of the Toolkit’s SHA-1
values would not have been helpful to Mr. Roberts because the
government relied on Agent Nordstrom’s review of the files, rather
than on the Toolkit’s SHA-1 values, to verify that those files
contained child pornography. Discovery of the Toolkit and its
methodologies was therefore not material to Mr. Roberts’ case. See
State v. Spry, 2001 UT App 75, ¶ 21, 21 P.3d 675 (explaining that
under the “good cause” standard in Utah Rule of Criminal
Procedure 16(a)(5), a defendant must “establish the materiality of the
requested records to the case” (internal quotation marks omitted)).
Mr. Roberts has made no attempt to refute this basis for denying his
motion.
    ¶39 In summary, Mr. Roberts has failed to meet his burden of
persuasion on appeal. And where the district court permitted
discovery of those aspects of the Wyoming Toolkit that were most
relevant to Mr. Roberts’ case, it did not abuse its discretion in
denying discovery of the entire Toolkit database, its methodologies,
and all of its SHA-1 values. We therefore affirm the district court’s
discovery ruling.
 IV. MR ROBERTS’ CONSTITUTIONAL CHALLENGE TO THE
         SEXUAL EXPLOITATION STATUTE FAILS
    ¶40 Mr. Roberts challenges the Sexual Exploitation Statute
under the Uniform Operation of Laws Provision of the Utah
Constitution. UTAH CONST . art. I, § 24 (“All laws of a general nature
shall have uniform operation.”). He argues that the statute creates at
least two unconstitutional classifications. First, he claims that the
statute unconstitutionally distinguishes between individuals who
can legally view child pornography (i.e., law enforcement officers
acting to further a criminal investigation and employees of
designated entities acting in good faith to report or prevent child
pornography) and those who may not. See UTAH CODE § 76-5a-3
(2009). Second, he argues that the statute unconstitutionally
distinguishes between prosecuting attorneys who encounter child
pornography as part of their work and similarly situated criminal
defense attorneys. We reject both arguments—the first on its merits
and the second due to a lack of standing.6


   6
    Mr. Roberts clearly has standing to raise his first challenge to the
Sexual Exploitation Statute because (1) he has suffered an injury (i.e.,
                                                          (continued...)

                                  15
                           STATE v. ROBERTS
                        Opinion of the Court

   A. The Classifications Created by the Sexual Exploitation Statute
                           Are Constitutional
    ¶41 For a statute to comply with the Uniform Operation of Laws
Provision of the Utah Constitution, “it is not enough that it be
uniform on its face. What is critical is that the operation of the law be
uniform.” Gallivan v. Walker, 2002 UT 89, ¶ 37, 54 P.3d 1069 (internal
quotation marks omitted). A statute is not uniform in its operation,
and is thus unconstitutional, if (1) “the statute creates any
classifications,” (2) those classifications “impose any disparate
treatment on persons similarly situated,” and (3) “the legislature had
[no] reasonable objective that warrants the disparity.” State v.
Robinson, 2011 UT 30, ¶ 17, 254 P.3d 183 (internal quotation marks
omitted).
    ¶42 Looking to the first Robinson requirement, Mr. Roberts
correctly argues that the Sexual Exploitation Statute creates certain
classifications. Most notably, it imposes criminal and civil liability on
individuals who “knowingly produce[], possess[], or possess[] with
intent to distribute” or “intentionally distribute[] or view[] child
pornography”; but the statute exempts from liability law
enforcement officers who encounter child pornography as part of a
criminal investigation and employees of certain organizations acting
in good faith and within the scope of their employment to report or
prevent child pornography. UTAH CODE § 76-5a-3 (2009).
    ¶43 Under the second Robinson requirement, however, these
classifications are not unconstitutional because they do not
discriminate between similarly situated individuals. The key
distinction between the individuals in each classification is the
context within which they view, possess, or distribute child
pornography. The statute exempts only those law enforcement
officers “acting within the scope of a criminal investigation” and
only employees of specific entities who are “acting within the scope
of employment” and “for the good faith performance of” reporting
or preventing child pornography. Id. Any law enforcement officer or


   6
    (...continued)
criminal prosecution and conviction), (2) that injury was caused by
the statute’s alleged unconstitutionality, and (3) we have the
authority to redress his injury if we determine the statute is
unconstitutional. See Carlton v. Brown, 2014 UT 6, ¶ 31, 323 P.3d 571
(explaining that to have standing, a party must show injury,
causation, and redressability).

                                   16
                         Cite as: 2015 UT 24
                        Opinion of the Court

employee of an exempt entity who knowingly or intentionally
produces, possesses, views, or distributes child pornography for any
other reason will be subject to the same criminal liability as other
individuals. Because this classification does not distinguish between
similarly situated individuals, it fails the second requirement of the
Robinson test. The Sexual Exploitation Statute therefore does not
violate the Uniform Operation of Laws Provision of the Utah
Constitution based on this classification.
B. Mr. Roberts Lacks Standing to Challenge the Constitutionality of the
 Sexual Exploitation Statute’s Disparate Treatment of Prosecutors and
                     Criminal Defense Attorneys
    ¶44 Mr. Roberts also contends that the Sexual Exploitation
Statute unconstitutionally distinguishes between prosecuting
attorneys and defense attorneys.7 Specifically, he argues that
prosecuting attorneys, are exempt under the Sexual Exploitation
Statute when viewing, possessing, or distributing child pornography
within the scope of a criminal investigation. Defense attorneys, on
the other hand, are granted no such exemption, and thus would be
in violation of the statute by possessing, viewing, or distributing
child pornography as part of their legal representation of a criminal
defendant.
    ¶45 On its face, the Sexual Exploitation Statute provides no
exemption for criminal defense attorneys who must view evidence
that may include child pornography in order to zealously advocate
for their clients. Before addressing the constitutionality of this
apparent oversight, however, we must first determine whether
Mr. Roberts has standing to bring this challenge. See Gregory v.
Shurtleff, 2013 UT 18, ¶ 9, 299 P.3d 1098 (“Since standing is a
jurisdictional requirement, we first must determine whether


   7
     In 2009, the Legislature amended the Sexual Exploitation Statute
to expressly exclude liability for law enforcement officers and
employees of exempt organizations. See UTAH CODE § 76-5b-201(6).
It did not, however, include an exemption for others involved in the
judicial process who may be required to view child pornography
during the course and within the scope of their employment. As a
practical matter, those involved in the judicial process, including
judges, court staff, jurors, and lawyers—both prosecuting and
defense—are unlikely to be prosecuted under this statute.
Nevertheless, the Legislature may wish to consider broadening the
exclusion to include such participants in the judicial process.

                                  17
                           STATE v. ROBERTS
                        Opinion of the Court

Appellants have standing to bring any of their claims.”); see also State
v. Tuttle, 780 P.2d 1203, 1207 (Utah 1989) (explaining that this court
may raise the issue of standing “sua sponte at any time”).
     ¶46 Standing requires that we view the constitutionality of a
statute from the perspective of the party raising the challenge. See
State v. Hoffman, 733 P.2d 502, 505 (Utah 1987) (“The constitutionality
of a statute is considered in light of the standing of the [party] who
raises the question and of its particular application in his case.”). To
establish standing under our traditional test, the party bringing a
constitutional challenge must show three things: (1) ”that [the party]
has been or will be adversely affected by the [challenged] actions,”
(2) that a “causal relationship [exists] between the injury to the party,
the [challenged] actions and the relief requested,” and (3) that the
relief requested is “substantially likely to redress the injury
claimed.” Utah Chapter of the Sierra Club v. Utah Air Quality Bd.,
2006 UT 74, ¶ 19, 148 P.3d 960 (second and fourth alterations in
original) (internal quotation marks omitted).
    ¶47 Under the first requirement, a party may only challenge a
statute “to the extent the alleged basis of its infirmity is, or will be,
applied to his detriment.” Hoffman, 733 P.2d at 505. In other words,
to obtain standing, a party challenging a statute must suffer an
injury as a result of the statute’s alleged unconstitutionality. In this
case, Mr. Roberts has not shown that he has been or will be injured
by the alleged unconstitutionality of the Sexual Exploitation Statute.
Instead, he raises only a hypothetical injury. He argues that because
defense attorneys could be subject to criminal and civil liability for
viewing evidence containing child pornography, their representation
of criminal defendants charged under the Sexual Exploitation Statute
will be hindered, thereby depriving criminal defendants of their
right to effective assistance of counsel. But Mr. Roberts cannot
establish an actual injury. First, Mr. Roberts bases his alleged injury
on defense counsel’s fear of prosecution—not his own. But a party
generally lacks standing “to contest the policies of the prosecuting
authority when he himself is neither prosecuted nor threatened with
prosecution.” Linda R.S. v. Richard D., 410 U.S. 614, 619 (1973).
    ¶48 And although Mr. Roberts alleges an indirect harm to
criminal defendants based on defense counsel’s fear of prosecution,
he has not shown that his counsel genuinely feared prosecution so
as to render his counsel’s representation ineffective. While Mr.
Roberts baldly asserts that his counsel was “unable to challenge the
provenance and character of the evidence against him” because
counsel was “at jeopardy of criminal prosecution” under the statute,

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                        Opinion of the Court

he wholly fails to substantiate this assertion. In fact, defense counsel
was given government-sanctioned access to the child-pornography
evidence at the RCLF without threat of prosecution. As the district
court noted in ruling on this issue, “[d]efense counsel has not alleged
that its access to the evidence was in any way inadequate under the
facts of this case.”
    ¶49 Defense counsel’s purported fear of prosecution and the
impact of that fear on counsel’s representation of Mr. Roberts are
speculative at best, and therefore are insufficient to demonstrate an
injury for purposes of standing. See Midvale City Corp. v. Haltom,
2003 UT 26, ¶ 22, 73 P.3d 334 (citing to United States Supreme Court
precedent for the proposition that “standing exists when fear of
criminal prosecution under allegedly unconstitutional statute is not
imaginary or wholly speculative”); Younger v. Harris, 401 U.S. 37, 42
(1971) (“[P]ersons having no fears of state prosecution except those
that are imaginary or speculative, are not to be accepted as
appropriate [parties] in such cases.”). Because Mr. Roberts cannot
demonstrate that he has or will suffer an actual injury based on the
Sexual Exploitation Statute’s disparate treatment of prosecutors and
criminal defense attorneys, he lacks traditional standing to challenge
the statute’s constitutionality.
    ¶50 We next consider whether Mr. Roberts has standing under
our alternative, public-interest test. See Gregory, 2013 UT 18, ¶ 25.
Parties who fail to gain standing under the traditional test may
nevertheless have standing “if they can show that they are an
appropriate party raising issues of significant public importance.”
Cedar Mountain Envtl., Inc. v. Tooele Cnty. ex rel. Tooele Cnty. Comm’n,
2009 UT 48, ¶ 8, 214 P.3d 95. But the party arguing alternative
standing has the burden of showing it satisfies the requirements of
this test. See Sierra Club, 2006 UT 74, ¶ 36.
   ¶51 Mr. Roberts has not presented any argument as to why he
should be granted standing under our alternative test. By not
presenting any argument, Mr. Roberts fails to satisfy his burden of
showing that he is entitled to public-interest standing.
    ¶52 In summary, we conclude that Utah’s Sexual Exploitation
Statute does not violate the Uniform Operation of Laws Provision of
the Utah Constitution because it does not treat similarly situated
individuals differently. And Mr. Roberts lacks standing to challenge
the constitutionality of the Sexual Exploitation Statute’s purported
disparate treatment of prosecuting and defense attorneys.



                                  19
                          STATE v. ROBERTS
                        Opinion of the Court

 V. THE DISTRICT COURT DID NOT ABUSE ITS DISCRETION
IN DENYING MR. ROBERTS’ MOTION TO PRECLUDE EXPERT
        TESTIMONY ON THE WYOMING TOOLKIT
    ¶53 Mr. Roberts’ final argument is that the district court erred
in denying his motion in limine to preclude expert testimony on the
Wyoming Toolkit. He contends that the Wyoming Toolkit does not
satisfy the reliability test for expert testimony required by rule 702
of the Utah Rules of Evidence. Mr. Roberts carries a heavy burden
in seeking reversal of this ruling because we grant district courts
broad discretion in determining the admissibility of expert
testimony. State v. Hollen, 2002 UT 35, ¶ 66, 44 P.3d 794. We will
therefore reverse the district court only if its decision “exceeds the
limits of reasonability.” Id. (internal quotation marks omitted). In
this case, the district court was well within its discretion in denying
Mr. Roberts’ motion. We therefore affirm.
    ¶54 Rule 702 of the Utah Rules of Evidence governs the
admissibility of expert witness testimony. It requires first that the
testimony of an expert witness “help the trier of fact to understand
the evidence or to determine a fact at issue.” UTAH R. EVID . 702(a).
Second, a party seeking to rely on expert scientific or technical
testimony may do so only “if there is a threshold showing that the
principles or methods that are underlying in the testimony (1) are
reliable, (2) are based upon sufficient facts or data, and (3) have been
reliably applied to the facts.” Id. 702(b). The advisory committee
notes to rule 702 emphasize that a party seeking to admit expert
testimony “is required to make only a ‘threshold’ showing . . .
[, which] requires only a basic foundational showing of indicia of
reliability for the testimony to be admissible, not that the opinion is
indisputably correct.” Id. 702 advisory committee note. This low
threshold permits district court judges, as the gatekeepers of
evidence, to err on the side of admission as long as there is some
minimal indication that the evidence is reliable. We note, however,
that the rigor of rule 702 “will vary depending on the complexity of
the particular case.” Eskelson ex rel. Eskelson v. Davis Hosp. & Med.
Ctr., 2010 UT 59, ¶ 15, 242 P.3d 762.
    ¶55 In this case, the district court held that expert testimony on
the Wyoming Toolkit satisfied rule 702's threshold of reliability. The
court found that the Toolkit’s use of SHA-1 values to identify child
pornography files was based on a reliable “mathematical formula”
that results in “an extraordinarily high degree of correlation between
the SHA-1 value and the actual image.” The court also found that the
Wyoming Toolkit uses software that is “readily available” and

                                  20
                          Cite as: 2015 UT 24
                         Opinion of the Court

“fairly common,” thereby refuting Mr. Roberts’ claim that the
Toolkit relies on undefined scientific methods. The court further
found that the officers using the Toolkit were well trained and that
adequate safeguards were in place to assure that a file identified by
the Toolkit was indeed child pornography. The court thus found that
the Wyoming Toolkit was reliable, was based upon sufficient facts
or data, and was reliably applied to the facts of Mr. Roberts’ case.
    ¶56 On appeal, Mr. Roberts argues that the expert testimony on
the Wyoming Toolkit did not satisfy the reliability requirements of
rule 702, but he provides no authoritative support for his claim. He
offers no evidence to refute the district court’s reliability
determination,8 cites to no legal or other authority that might
undermine the reliability of the Wyoming Toolkit, and points to
nothing in the record to support his position. Instead, he simply
asserts without any supporting authority that the Toolkit is not as
reliable as the district court found it to be. In short, Mr. Roberts has
failed to provide any evidence that the district court abused its
discretion in admitting the expert testimony on the Wyoming
Toolkit. Contrary to Mr. Roberts’ unsupported claims, the State
provided substantial evidence of the Toolkit’s accuracy and the
validity of its methodologies. Based on this evidence, the district
court’s finding that the Toolkit was reliable was supported by the
evidence and therefore met rule 702's threshold reliability
requirement.
    ¶57 In summary, we affirm the district court’s denial of Mr.
Roberts’ motion in limine because Mr. Roberts has not provided any
evidence that the district court abused its discretion under rule 702
of the Utah Rules of Evidence by admitting expert testimony about
the Wyoming Toolkit.
                            CONCLUSION
    ¶58 We affirm each of the district court’s pretrial rulings in this
case. First, the district court correctly found that the State’s use of the
Wyoming Toolkit did not constitute a search under the Fourth
Amendment because Mr. Roberts had no reasonable expectation of
privacy in files he publicly shared on a P2P network. Nor did an


   8
     Mr. Roberts could have argued that he was unable to present
evidence about the Toolkit because he was denied discovery. But he
has neither raised nor briefed that argument here, so we decline to
address it. See Diversified Holdings, L.C. v. Turner, 2002 UT 129,
¶ 10 n.4, 63 P.3d 686.

                                    21
                          STATE v. ROBERTS
                        Opinion of the Court

unlawful search take place when law enforcement obtained
Mr. Roberts’ subscription information from Emery Telecom. Second,
the district court did not abuse its discretion in limiting Mr. Roberts’
discovery of the Wyoming Toolkit database and its methodologies.
Third, the district court correctly dismissed Mr. Roberts’
constitutional challenges to the Sexual Exploitation Statute. Finally,
the district court did not abuse its discretion in admitting expert
testimony on the Wyoming Toolkit. We therefore affirm Mr. Roberts’
conviction for violation of the Sexual Exploitation Statute.




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