By Christo­pher J. Ryd­berg 1

Advances in tech­nol­o­gy raise new and chal­leng­ing ques­tions for courts in inter­pret­ing the pro­tec­tions of the Fourth and Fifth Amend­ments. As the Supreme Court not­ed in Riley v. Cal­i­for­nia, search­es of cell phones “typ­i­cal­ly expose to the gov­ern­ment far more [pri­vate infor­ma­tion] than the most exhaus­tive search of a house,” and the “pos­si­ble intru­sion on pri­va­cy is not phys­i­cal­ly lim­it­ed in the same way when it comes to cell phones.” 2 Cell phones have the capac­i­ty to store vast amounts of pri­vate infor­ma­tion about our every­day lives, 3 and the dis­tinct and diverse types of data they may store tend to expose to law enforce­ment offi­cers a com­plete pic­ture of the owner’s life. As Jus­tice Sotomay­or not­ed in Unit­ed States v. Jones, indi­vid­ual, dis­crete pieces of infor­ma­tion — even if not indi­vid­u­al­ly pri­vate or incrim­i­nat­ing — may in sum become a mosa­ic, reveal­ing the most inti­mate details of an individual’s life. 4

These unique con­cerns pose chal­lenges to courts seek­ing to ensure that the Fourth and Fifth Amend­ments retain mean­ing in the dig­i­tal age. Bal­anc­ing law enforce­ment inter­ests against indi­vid­ual pri­va­cy rights, and the right against self-incrim­i­na­tion, requires height­ened judi­cial scruti­ny and man­age­ment to ensure that law enforce­ment does not run roughshod over civ­il lib­er­ties while in pur­suit of sus­pects. This is even more impor­tant in the age of ter­ror­ism, as the fear of ter­ror can blind gov­ern­ment actors in their attempts to pre­vent anoth­er attack, focus­ing sin­gle-mind­ed­ly on their tar­get while ignor­ing coun­ter­vail­ing con­sti­tu­tion­al pri­va­cy con­sid­er­a­tions. Accord­ing­ly, this Con­tri­bu­tion will argue that the Fifth Amend­ment pre­vents gov­ern­ment actors from phys­i­cal­ly com­pelling sub­jects to unlock their cell phones with their fin­ger­print and there­by obtain­ing incrim­i­nat­ing evi­dence. This Con­tri­bu­tion will also argue that the Fourth Amend­ment requires greater par­tic­u­lar­i­ty in cell phone search­es, spec­i­fy­ing how the phone will be searched, and that the use of the plain view doc­trine in cell phone search­es is incon­sis­tent with Fourth Amend­ment rea­son­able­ness requirements.


The Fifth Amend­ment to the U.S. Con­sti­tu­tion pro­vides that no per­son “shall be com­pelled in any crim­i­nal case to be a wit­ness against him­self.” 5 The Fifth Amend­ment pro­tects a wide range of com­pelled com­mu­ni­ca­tions deemed to be tes­ti­mo­ni­al, or com­mu­nica­tive, in nature. 6 In par­tic­u­lar, the Fifth Amend­ment pro­tects against gov­ern­ment com­pul­sion by means of force or oth­er coer­cive tech­niques. 7 Includ­ed in these pro­tec­tions are any “tes­ti­mo­ni­al mate­ri­als, such as books and papers,” because these things “are gen­er­al­ly lit­tle more than an exten­sion of [one’s] per­son.” 8 The amend­ment does not, how­ev­er, guard against com­pul­sion of evi­dence that is mere­ly demon­stra­tive, or non-tes­ti­mo­ni­al, in nature. 9 This non-tes­ti­mo­ni­al excep­tion to the priv­i­lege against self-incrim­i­na­tion encom­pass­es sev­er­al types of phys­i­cal evi­dence, includ­ing: voice exem­plars 10, hand­writ­ing exem­plars 11, par­tic­i­pa­tion in line­ups 12, blood sam­ples 13, cloth­ing 14

The Fourth Amend­ment of the U.S. Con­sti­tu­tion pro­tects against unjus­ti­fied gov­ern­ment intru­sion into the pri­vate affairs of cit­i­zens. 15 The Amend­ment con­tains two prin­ci­pal claus­es – the Rea­son­able­ness Clause and the War­rant Clause. 16 Gen­er­al­ly, the Fourth Amend­ment holds that a search is unrea­son­able unless con­duct­ed with a war­rant sup­port­ed by prob­a­ble cause. 17

For a war­rant to com­ply with the Fourth Amend­ment of the U.S. Con­sti­tu­tion, it must be based on prob­a­ble cause and be rea­son­able, and it must “par­tic­u­lar­ly describ[e] the place to be searched, and the per­sons or things to be seized.” 18 This require­ment to describe with par­tic­u­lar­i­ty where the search would take place and what will be seized arose as a pro­tec­tion against gen­er­al war­rants, which per­mit­ted law enforce­ment the wide-rang­ing author­i­ty to search at will with­out mean­ing­ful checks. 19 As such, when search­ing phys­i­cal loca­tions, war­rants should be tai­lored to spe­cif­ic loca­tions where there is prob­a­ble cause to believe evi­dence is like­ly to be found. 20 “If police approach a mag­is­trate with an informant’s tes­ti­mo­ny that Sal­ly Sus­pect is involved in nar­cotics traf­fick­ing, the mag­is­trate should not auto­mat­i­cal­ly issue a war­rant for Sally’s house, her office, her car, and her per­son.” 21 Sim­i­lar­ly, with­in phys­i­cal struc­tures, the same con­straints apply — police may only search where the evi­dence may rea­son­ably be found. 22

There are, how­ev­er, excep­tions to this gen­er­al pref­er­ence for war­rants. The “plain view” doc­trine is one of them. 23 This seizure is per­mis­si­ble even with­out a war­rant because it would not pro­duce an addi­tion­al inva­sion of pri­va­cy. 24 For a seizure of evi­dence under the plain view excep­tion to be per­mis­si­ble, the item must be in plain view of an offi­cer who is legit­i­mate­ly on the premis­es with a law­ful right of action to the object, and it must be imme­di­ate­ly appar­ent that the object in ques­tion is con­tra­band. 25


The coerced unlock­ing of a suspect’s cell phone by use of her fin­ger­print should be deemed tes­ti­mo­ni­al because it demon­strat­ed her con­trol over the phone. The Supreme Court has held that the act of pro­duc­ing doc­u­ments could be deemed tes­ti­mo­ni­al, by virtue of the fact that the pro­duc­tion com­mu­ni­cat­ed own­er­ship and con­trol over the evi­dence. 26 Although the Court in Fish­er held that the nature of pro­duc­tion should be deter­mined on a case-by-case basis, rather than imple­ment­ing a bright-line rule, its rea­son­ing demon­strates that there are at least some times when the act of pro­duc­ing evi­dence could itself be tes­ti­mo­ni­al. 27 The forced unlock­ing of a smart­phone should be deemed one of those tes­ti­mo­ni­al acts of pro­duc­tion. The act of unlock­ing a cell phone with a fin­ger­print demon­strates con­trol over the phone and the com­mu­nica­tive evi­dence con­tained there­in, as the bio­met­ric encryp­tion is a direct link to tes­ti­mo­ni­al mate­r­i­al with­in the phone. The Supreme Court’s jurispru­dence pro­tects evi­dence that is a “link in the chain” to com­mu­nica­tive evi­dence, even if that link would not nor­mal­ly receive Fifth Amend­ment pro­tec­tion. As the Court not­ed in Hoff­man v. Unit­ed States, “[t]he priv­i­lege afford­ed not only extends to answers that would in them­selves sup­port a con­vic­tion under a fed­er­al crim­i­nal statute but like­wise embraces those which would fur­nish a link in the chain of evi­dence need­ed to pros­e­cute the claimant for a fed­er­al crime.” 28 Sim­i­lar­ly, in Unit­ed States v. Hubbell, the Court not­ed that infor­ma­tion “that may ‘lead to incrim­i­nat­ing evi­dence’ is priv­i­leged even if the infor­ma­tion itself is not incul­pa­to­ry.” 29 The use of an individual’s fin­ger­print to unlock her cell phone is exact­ly such a link and thus deserves Fifth Amend­ment protection.

The forced use of an individual’s fin­ger­print to open her cell phone should be viewed in light of the pur­pose for which the fin­ger­print was used: as a pass­code and a means to access vast quan­ti­ties of high­ly per­son­al infor­ma­tion con­tained on the phone. Phys­i­cal­ly forc­ing a sus­pect to place her fin­ger on her phone and unlock it falls square­ly with­in the evil intend­ed to be pre­vent­ed by the Fifth Amend­ment. 30 Such phys­i­cal coer­cion to pro­duce incrim­i­nat­ing evi­dence is incom­pat­i­ble with the basic tenets of the Fifth Amendment.

This pur­pose-dri­ven analy­sis is par­tic­u­lar­ly impor­tant giv­en the arti­fi­cial dis­tinc­tion a con­trary posi­tion would cre­ate. Cur­rent­ly, forc­ing an indi­vid­ual to divulge a pass­code would run afoul of Fifth Amend­ment pro­tec­tions, while com­pelling pro­duc­tion of a phys­i­cal key would not. 31 Accord­ing­ly, in Unit­ed States v. Kirschn­er, the Gov­ern­ment issued a sub­poe­na for pass­words to the defendant’s com­put­er, seek­ing evi­dence of child pornog­ra­phy. 32 The Dis­trict Court held this to be a vio­la­tion of the Fifth Amend­ment priv­i­lege, rul­ing that the pro­duc­tion of the pass­words was tes­ti­mo­ni­al and divulged infor­ma­tion that Kirschn­er knew would con­vict him. 33

A mechan­i­cal appli­ca­tion of Fifth Amend­ment prece­dent may relate a fin­ger­print to a key, but such a read­ing miss­es the for­est for the trees and evis­cer­ates the Amendment’s pro­tec­tion in the dig­i­tal era. The fin­ger­print, as used to unlock a cell phone, is far more than mere iden­ti­fi­ca­tion that the Schmer­ber Court con­tem­plat­ed. It is a direct link to com­mu­nica­tive and pos­si­bly incrim­i­nat­ing evi­dence. Con­trary hold­ings would cre­ate the per­verse result that the Fifth Amend­ment pro­tects the con­sumer who choses to use a pass­word, but not the indi­vid­ual who used bio­met­ric pro­tec­tion — even though the lat­ter makes her choice know­ing that bio­met­ric encryp­tion is more secure than a four-dig­it pass­code. 34 This is a dis­tinc­tion with­out a dif­fer­ence, for both the pass­code and the fin­ger­print are sim­ply the means to access tes­ti­mo­ni­al con­tent on the phone. This would be an unten­able and illog­i­cal result — the con­sumer who seeks extra pro­tec­tion through bio­met­ric secu­ri­ty in the end receives less.

Search war­rants that pur­port to autho­rize broad search­es of all data con­tained on a cell phone should be deemed over­broad and with­out the par­tic­u­lar­i­ty demand­ed by the Fourth Amend­ment. Gen­er­al­ly, elec­tron­ic search­es present very sig­nif­i­cant chal­lenges to the par­tic­u­lar­i­ty require­ment. Advance­ments in tech­nol­o­gy mean that vast amounts of data can be stored on a hard dri­ve that fits in a pock­et. In par­tic­u­lar, the mod­ern smart­phone func­tions in such a wide vari­ety of ways — phone, cal­en­dar, email, tex­ting, loca­tion track­ing — that a search with­out guide­lines to cab­in gov­ern­ment dis­cre­tion could reveal the most inti­mate aspects of our lives. The risk in elec­tron­ic search cas­es of those “wide-rang­ing explorato­ry search­es” pro­hib­it­ed by the Fourth Amend­ment is height­ened. 35 As a result, where search war­rants have pur­port­ed to autho­rize broad search­es of elec­tron­ic equip­ment, courts have held the war­rant to vio­late the par­tic­u­lar­i­ty require­ment. 36Absent restric­tions, the gov­ern­ment could search through the entire­ty of a suspect’s phone and its many appli­ca­tions. Such a broad search close­ly resem­bles the gen­er­al war­rants so reviled at the found­ing, 37 and for that rea­son, war­rants autho­riz­ing search­es of the entire­ty of a cell phone can­not pass con­sti­tu­tion­al muster.

The plain view doctrine’s appli­ca­tion to dig­i­tal evi­dence, and to cell phones in par­tic­u­lar, pos­es sim­i­lar chal­lenges. For both com­put­ers and cell phones, hard dri­ves can store vast amounts of pri­vate infor­ma­tion about our every­day lives. Mod­ern cell­phones com­pound these con­cerns, because they func­tion as “cam­eras, video play­ers, rolodex­es, cal­en­dars, tape recorders, libraries, diaries, albums, tele­vi­sions, maps, [and] news­pa­pers” all at once, in a com­pact pack­age that will fit in the palm of your hand. 38 In this sense, they are qual­i­ta­tive­ly dif­fer­ent from, for exam­ple, a stor­age cab­i­net — not mere­ly because their stor­age capac­i­ty exceeds even a room full of fil­ing cab­i­nets, but because of the myr­i­ad types of doc­u­ments they can hold.

The fact that dig­i­tal devices, includ­ing com­put­ers and phones, can hold such a vari­ety of doc­u­ments presents a chal­leng­ing ques­tion for the appli­ca­tion of the plain view doc­trine. When law enforce­ment search­es elec­tron­ic devices, it is not just pos­si­ble but in fact high­ly like­ly that they will encounter pri­vate infor­ma­tion that is unre­lat­ed to the tar­get of the search, even if the search is extreme­ly focused. 39 This lack of effec­tive con­straints on where and how law enforce­ment may search leads to a weak­en­ing of the par­tic­u­lar­i­ty require­ment and runs the risk of per­mit­ting gen­er­al war­rants, the very evil the Fourth Amend­ment sought to rem­e­dy. 40 “[D]igital evi­dence dimin­ish­es the reg­u­la­to­ry effect of the par­tic­u­lar­i­ty require­ment” because the evi­dence sought could be locat­ed any­where on the hard dri­ve or cell phone and thus increas­es the fre­quen­cy with which the plain view doc­trine could be invoked on find­ing unre­lat­ed but nonethe­less incrim­i­nat­ing evi­dence. 41 Search­ing a cell phone or a com­put­er is qual­i­ta­tive­ly dif­fer­ent than tan­gi­ble objects, because the “pos­si­ble intru­sion on pri­va­cy is not phys­i­cal­ly lim­it­ed in the same way when it comes to cell phones.” 42

These sig­nif­i­cant con­cerns coun­sel in favor of reject­ing the plain view doc­trine in elec­tron­ic search cas­es and for requir­ing greater par­tic­u­lar­i­ty in search war­rants for cell phones. These pro­to­cols are crit­i­cal to pre­serv­ing the core pur­pose and integri­ty of both the Fourth Amend­ment and the plain view excep­tion to the pref­er­ence for war­rants. In the case of dig­i­tal search­es, allow­ing the plain view doc­trine to exist would allow the excep­tion to swal­low the rule — that is, any search war­rant for a com­put­er or cell phone would become func­tion­al­ly a gen­er­al war­rant, allow­ing law enforce­ment to search through each indi­vid­ual file or piece of infor­ma­tion. Unteth­ered from its ground­ing in the rea­son­able­ness clause of the Fourth Amend­ment, the plain view excep­tion would allow “[t]he process of seg­re­gat­ing elec­tron­ic data that is seiz­able [sic] from that which is not . . . [to] become a vehi­cle for the gov­ern­ment to gain access to data which it has no prob­a­ble cause to col­lect.” 43

Riley sup­ports the propo­si­tion that elec­tron­ic search­es should be treat­ed dif­fer­ent­ly than oth­er search­es of phys­i­cal objects or loca­tions. In Riley, the Court sin­gled out the unique qual­i­ties of cell phones and how they present nov­el pri­va­cy con­cerns in hold­ing that the search inci­dent to a law­ful arrest excep­tion does not apply to cell phones. 44 Those same unique qual­i­ties of cell phones also dic­tate that the plain view excep­tion should not apply. “The exist­ing plain view excep­tion remains root­ed in the con­tin­gent dynam­ics of phys­i­cal evi­dence col­lec­tion,” 45 while the rel­a­tive­ly new world of dig­i­tal evi­dence presents vast­ly dif­fer­ent con­cerns about the scope of gov­ern­ment intru­sion. Specif­i­cal­ly, the Riley Court not­ed that “[a] con­clu­sion that inspect­ing the con­tents of an arrestee’s pock­ets works no sub­stan­tial addi­tion­al intru­sion on pri­va­cy beyond the arrest itself may make sense as applied to phys­i­cal items, but any exten­sion of that rea­son­ing to dig­i­tal data has to rest on its own bot­tom.” 46 The same con­cerns that ani­mat­ed the Court in Riley to carve out a cell-phone excep­tion to the search inci­dent to arrest doc­trine are at play here as well, and call for the cre­ation of a sim­i­lar exception.

The bal­ance between law enforce­ment and pri­va­cy inter­ests — care­ful­ly estab­lished over decades — has been upend­ed by rapid advance­ments in tech­nol­o­gy. It is crit­i­cal that courts respond appro­pri­ate­ly to these advances rather than mechan­i­cal­ly apply­ing prece­dent more appro­pri­ate­ly suit­ed to the col­lec­tion of phys­i­cal evi­dence. 47 The Fifth Amend­ment must be held to pro­tect a sus­pect from being phys­i­cal­ly com­pelled to pro­vide her fin­ger­print to unlock her cell phone. Sim­i­lar­ly, the Fourth Amendment’s pro­tec­tions should apply equal­ly, if not more so, for cell phones and oth­er dig­i­tal evi­dence. War­rants should spec­i­fy with par­tic­u­lar­i­ty what specif­i­cal­ly on the phone will be searched and how. Final­ly, the plain view doc­trine should not apply in this case. As an excep­tion to the gen­er­al pref­er­ence for war­rants, it no longer has its intend­ed effect in the con­text of dig­i­tal search­es, and accord­ing­ly should not be permitted.


  1. Christo­pher J. Ryd­berg is a 2L at New York Uni­ver­si­ty School of Law. This piece is a com­men­tary on the 2017 Evan A. Evans Con­sti­tu­tion­al Law Moot Court Com­pe­ti­tion host­ed by the Uni­ver­si­ty of Wis­con­sin Moot Court Board. The fact pat­tern of the com­pe­ti­tion involved law enforce­ment seek­ing to search the cell phone of an indi­vid­ual believed to be part of a fic­tion­al ter­ror­ist orga­ni­za­tion. Law enforce­ment obtained a war­rant that autho­rized a search of “any and all data” on the phone relat­ed to the ter­ror­ist net­work. The ques­tions pre­sent­ed were whether the Fifth Amend­ment pre­vent­ed law enforce­ment from phys­i­cal­ly com­pelling the defen­dant to unlock his cell phone with his fin­ger­print, whether the search war­rant lacked par­tic­u­lar­i­ty under the Fourth Amend­ment, and whether the plain view excep­tion to the war­rant require­ment should apply in cell phone search­es. The views expressed in this arti­cle do not nec­es­sar­i­ly rep­re­sent the views of the author on this point of law. Rather, this arti­cle is a dis­til­la­tion of one side of an argu­ment assigned to the author at the 2017 Evan A. Evans Con­sti­tu­tion­al Law Moot Court Com­pe­ti­tion. For anoth­er com­men­tary on this com­pe­ti­tion, see The Impor­tance of Pri­va­cy in Shared Spaces.
  2. Riley v. Cal­i­for­nia, 134 S. Ct. 2473, 2491, 2489 (2014) (empha­sis in orig­i­nal).
  3. See Orin S. Kerr, Search­es and Seizures in a Dig­i­tal World, 119 Harv. L. Rev. 532, 532 (2005).
  4. Unit­ed States v. Jones, 565 U.S. 400, 416 (2012) (Sotomay­or, J., dis­sent­ing) (ques­tion­ing “whether peo­ple rea­son­ably expect that their move­ments will be record­ed and aggre­gat­ed in a man­ner that enables the Gov­ern­ment to ascer­tain, more or less at will, their polit­i­cal and reli­gious beliefs, sex­u­al habits, and so on.”).
  5. U.S. Con­st. amend. V (“No per­son . . . shall be com­pelled in any crim­i­nal case to be a wit­ness against him­self”).
  6. See Fish­er v. Unit­ed States, 425 U.S. 391, 409 (1976).
  7. See Holt v. Unit­ed States, 218 U.S. 245, 252–53 (1910); see also Unit­ed States v. White, 322 U.S. 694, 698 (1944) (explain­ing that “[t]he con­sti­tu­tion­al priv­i­lege against self-incrim­i­na­tion . . . is designed to pre­vent [the gov­ern­ment from] forc[ing] from the lips of the accused indi­vid­ual the evi­dence nec­es­sary to con­vict him or to force him to pro­duce and authen­ti­cate any per­son­al doc­u­ments or effects that might incrim­i­nate him.”).
  8. Fish­er, 425 U.S. at 420 (1976) (Bren­nan, J., con­cur­ring).
  9. See Schmer­ber v. Cal­i­for­nia, 384 U.S. 757, 764 (1966) (“[T]the priv­i­lege is a bar against com­pelling ‘com­mu­ni­ca­tions’ or ‘tes­ti­mo­ny,’ but that com­pul­sion which makes a sus­pect or accused the source of ‘real or phys­i­cal evi­dence’ does not vio­late it.”).
  10. Unit­ed States v. Dion­i­sio, 410 U.S. 1, 7 (1973).
  11. Gilbert v. Cal­i­for­nia, 388 U.S. 263, 266–67 (1967).
  12. Unit­ed States v. Wade, 388 U.S. 218, 221–22 (1967).
  13. Schmer­ber, 384 U.S. at 765.
  14. Holt v. Unit­ed States, 218 U.S. 245, 252–53 (1910)./ 48, and the col­lec­tion of fin­ger­prints dur­ing the post-arrest book­ing process. 49See Schmer­ber, 384 U.S. at 764 (“[B]oth fed­er­al and state courts have usu­al­ly held that [the Fifth Amend­ment] offers no pro­tec­tion against com­pul­sion to sub­mit to fin­ger­print­ing.”).
  15. See U.S. Con­st. amend. IV.
  16. See Luis G. Stelzn­er, The Fourth Amend­ment: The Rea­son­able­ness and War­rant Claus­es, 10 N.M. L. Rev. 33, 33 (1979).
  17. See, e.g., Cal­i­for­nia v. Car­ney, 471 U.S. 386, 390 (1985) (“This fun­da­men­tal right is pre­served by a require­ment that search­es be con­duct­ed pur­suant to a war­rant issued by an inde­pen­dent judi­cial offi­cer.”).
  18. U.S. Con­st. amend. IV.
  19. See, e.g., Ashcroft v. al-Kidd, 563 U.S. 731, 742 (2011) (“The Fourth Amend­ment was a response to the Eng­lish Crown’s use of gen­er­al war­rants, which often allowed roy­al offi­cials to search and seize what­ev­er and whomev­er they pleased while inves­ti­gat­ing crimes or affronts to the Crown.”).
  20. See, e.g., Unit­ed States v. George, 975 F.2d 72, 76 (2d Cir. 1992) (“Absent some lim­i­ta­tion cur­tail­ing the offi­cers’ dis­cre­tion when exe­cut­ing the war­rant, the safe­guard of hav­ing a mag­is­trate deter­mine the scope of the search is lost.”)
  21. Adam M. Ger­showitz, The Post-Riley Search War­rant: Search Pro­to­cols and Par­tic­u­lar­i­ty in Cell Phone Search­es, 69 Van­der­bilt L. Rev. 585, 589 (2015).
  22. See id. (“If police have a search war­rant for a stolen fifty-inch tele­vi­sion, they can­not look in the microwave.”).
  23. See Coolidge v. New Hamp­shire, 403 U.S. 443, 465 (1971) (plu­ral­i­ty opin­ion) (“It is well estab­lished that under cer­tain cir­cum­stances the police may seize evi­dence in plain view with­out a war­rant.”).
  24. See Ari­zona v. Hicks, 480 U.S. 321, 325 (1987) (not­ing that an inspec­tion of items in plain view “would not have con­sti­tut­ed an inde­pen­dent search, because it would have pro­duced no addi­tion­al inva­sion of respon­den­t’s pri­va­cy inter­est”).
  25. See Hor­ton v. Cal­i­for­nia, 496 U.S. 128, 136–37 (1990) (hold­ing that a plain view seizure requires the “incrim­i­nat­ing char­ac­ter must . . . be ‘imme­di­ate­ly appar­ent’” and that the offi­cer must “have a law­ful right of access to the object itself”).
  26. See Fish­er v. Unit­ed States, 425 U.S. 391, 410 (1976) (“[T]he act of pro­duc­ing evi­dence in response to a sub­poe­na nev­er­the­less has com­mu­nica­tive aspects of its own”).
  27. Id. (“These ques­tions per­haps do not lend them­selves to cat­e­gor­i­cal answers; their res­o­lu­tion may instead depend on the facts and cir­cum­stances of par­tic­u­lar cas­es or class­es there­of.”).
  28. Hoff­man v. Unit­ed States, 341 U.S. 479, 486 (1951).
  29. Unit­ed States v. Hubbell, 530 U.S. 27, 38 (2000) (quot­ing Doe v. Unit­ed States, 487 U.S. 201, 208, n.6 (1988)).
  30. See Unit­ed States v. White, 322 U.S. 694, 698 (1944) (“Phys­i­cal tor­ture and oth­er less vio­lent but equal­ly rep­re­hen­si­ble modes of com­pelling the pro­duc­tion of incrim­i­nat­ing evi­dence are there­by avoid­ed.”).
  31. See Hubbell, 530 U.S. at 41 (find­ing that Fifth Amend­ment would pro­tect against forced dis­clo­sure of “com­bi­na­tion to a wall safe,” but “not being forced to sur­ren­der the key to a strong­box”).
  32. See Unit­ed States v. Kirschn­er, 823 F. Supp. 2d 665, 666 (E.D. Mich. 2010).
  33. Id. at 669.
  34. See About Touch ID secu­ri­ty on iPhone and iPad, Apple (Nov. 3, 2015), (“Your fin­ger­print is one of the best pass­codes in the world.”).
  35. See Mary­land v. Gar­ri­son, 480 U.S. 79, 84 (1987).
  36. See Unit­ed States v. Zemlyan­sky, 945 F. Supp. 2d 438, 458 (S.D.N.Y. 2013) (dis­al­low­ing a war­rant for “indis­crim­i­nate­ly permit[ting] the search of all [c]omputers and [t]humb dri­ves” for lack­ing par­tic­u­lar­i­ty); Unit­ed States v. Rosa, 626 F.3d 56, 58 (2d Cir. 2010) (find­ing that a war­rant per­mit­ting offi­cers to search “com­put­er equip­ment” and “elec­tron­ic dig­i­tal stor­age media” lacked par­tic­u­lar­i­ty).
  37. See Ashcroft v. al-Kidd, 563 U.S. 731, 742–43 (2011) (“The Fourth Amend­ment was a response to the Eng­lish Crown’s use of gen­er­al war­rants, which often allowed roy­al offi­cials to search and seize what­ev­er and whomev­er they pleased while inves­ti­gat­ing crimes or affronts to the Crown.”).
  38. Riley v. Cal­i­for­nia, 134 S. Ct. 2473, 2489 (2014).
  39. See Kerr, supra note 3, at 538.
  40. See id. at 565 (not­ing that “com­put­er tech­nolo­gies may allow war­rants that are par­tic­u­lar on their face to become gen­er­al war­rants in prac­tice”).
  41. Id.
  42. Riley, 134 S. Ct. at 2489.
  43. Unit­ed States v. Com­pre­hen­sive Drug Test­ing Inc., 621 F.3d 1162, 1177 (9th Cir. 2010).
  44. See Riley, 134 S. Ct. at 2489.
  45. Kerr, supra note 3, at 571.
  46. Riley, 134 S. Ct. at 2489.
  47. As the Court in Riley not­ed, say­ing dig­i­tal evi­dence should be treat­ed just like phys­i­cal evi­dence “is like say­ing a ride on horse­back is mate­ri­al­ly indis­tin­guish­able from a flight to the moon. Both are ways of get­ting from point A to point B, but lit­tle else jus­ti­fies lump­ing them togeth­er.” Riley, 134 S. Ct. at 2488.