Opinion of the Court
mation relevant to the crime, the arrestee's identity, or officer safety will be discovered. See Brief for United States in No. 13-212, at 51-53. This approach would again impose few meaningful constraints on officers. The proposed categories would sweep in a great deal of information, and officers would not always be able to discern in advance what information would be found where.
We also reject the United States' final suggestion that officers should always be able to search a phone's call log, as they did in Wurie's case. The Government relies on Smith V. Maryland, 442 U. S. 735 (1979), which held that no warrant was required to use a pen register at telephone company premises to identify numbers dialed by a particular caller. The Court in that case, however, concluded that the use of a pen register was not a "search" at all under the Fourth Amendment. See id., at 745-746. There is no dispute here that the officers engaged in a search of Wurie's cell phone. Moreover, call logs typically contain more than just phone numbers; they include any identifying information that an individual might add, such as the label "my house" in Wurie's case.
Finally, at oral argument California suggested a different limiting principle, under which officers could search cell phone data if they could have obtained the same information from a pre-digital counterpart. See Tr. of Oral Arg. in No. 13-132, at 38-43; see also Flores-Lopez, 670 F. 3d, at 807 ("If police are entitled to open a pocket diary to copy the owner's address, they should be entitled to turn on a cell phone to learn its number."). But the fact that a search in the pre-digital era could have turned up a photograph or two in a wallet does not justify a search of thousands of photos in a digital gallery. The fact that someone could have tucked a paper bank statement in a pocket does not justify a search of every bank statement from the last five years. And to make matters worse, such an analogue test would allow law enforcement to search a
