State v. Roberts, 2015 UT 24

Background

ICAC used the Wyoming Toolkit (a database of SHA-1 hashes + software that scans Gnutella P2P network) to identify files shared from an IP address as suspected child pornography.
Agent Nordstrom confirmed the files matched known child-pornography SHA-1 values, subpoenaed Emery Telecom for subscriber info, and obtained a search warrant for Roberts’ home and later his laptop; forensic exam found images and videos.
Roberts was charged with 30 counts of sexual exploitation of a minor; he conditionally pled guilty to 5 counts and appealed several pretrial rulings.
Pretrial motions: (1) suppression (Wyoming Toolkit and subpoena/IP lookup as illegal search), (2) compel discovery of the Toolkit and its methodologies/SHA-1 list, (3) facial and as-applied challenge to Utah’s Sexual Exploitation Statute under Art. I § 24, and (4) motion in limine to exclude expert testimony about the Toolkit under Rule 702.
District court denied suppression, limited discovery (provided SHA-1s relevant to Roberts’ files but denied full Toolkit disclosure), rejected constitutional challenges, and admitted expert testimony; Utah Supreme Court affirmed.

Issues

Issue	Plaintiff's Argument (Roberts)	Defendant's Argument (State)	Held
Whether use of Wyoming Toolkit and identification of shared files on Gnutella constituted a Fourth Amendment search	Toolkit is like Kyllo thermal imaging: a warrantless, technologically enabled intrusion into private computer contents, so evidence should be suppressed	Files were publicly shared on a P2P network; no reasonable expectation of privacy in publicly shared files; Toolkit only identified hashes, not private content	No search: defendant had no reasonable expectation of privacy in files he publicly shared; Toolkit use did not violate Fourth Amendment
Validity of subpoena to ISP for subscriber/IP information	Administrative subpoena for subscriber info was improper	Subpoena complied with law as of 2009	Subpoena valid under law in effect at the time; statutory changes after 2009 not applied retroactively
Whether district court abused discretion by denying full discovery of the Wyoming Toolkit (methodology, full SHA-1 database)	Full disclosure of Toolkit and methodologies (and all SHA-1s) was necessary to verify alleged images and to challenge reliability	State provided relevant SHA-1s and investigative verification; disclosure of full methods/database would harm law enforcement investigations and was not material	No abuse of discretion: court ordered disclosure of information relevant to Roberts’ files but properly denied wholesale disclosure of Toolkit and full database
Admissibility of expert testimony about the Wyoming Toolkit under Utah R. Evid. 702	Toolkit methods are not demonstrated reliable; defense had insufficient opportunity to test reliability	Toolkit uses common, public techniques (SHA-1 hashing), officers used it as an investigative tool and performed independent verification; State met Rule 702 threshold	No abuse of discretion: trial court’s threshold reliability finding was supported and expert testimony admissible

Key Cases Cited

Kyllo v. United States, 533 U.S. 27 (2001) (use of non‑public thermal imaging to detect interior details of home held to be a search)
Katz v. United States, 389 U.S. 347 (1967) (reasonable expectation of privacy test)
Linda R.S. v. Richard D., 410 U.S. 614 (1973) (limits third‑party standing to challenge prosecution policy)
United States v. Perrine, 518 F.3d 1196 (10th Cir.) (no reasonable expectation of privacy in subscriber information given to ISP)
United States v. Hill, 750 F.3d 982 (8th Cir.) (no reasonable expectation of privacy in files shared via P2P networks)
State v. Robinson, 254 P.3d 183 (Utah 2011) (Uniform Operation of Laws analysis for classifications)
State v. Tripp, 227 P.3d 1251 (Utah 2010) (standard of review for suppression rulings)
State v. Belgard, 615 P.2d 1274 (Utah 1980) (discussion of applying intervening legal changes to cases on appeal)