The United States Supreme Court held in Riley v. California that the police generally may not, without a warrant, search digital information on a cellphone seized from an individual who has been arrested.
It seems like the what is on the physical cell phone is just the root of the search and seizure issue. Many cell phones are connected to much more information than the physical device can hold. Extending the capacity to access documents, cloud storage can vastly increase what a cell phone has access to.
Acting as an extension of the physical cell phone, it is not completely clear what the Fourth Amendment search and seizure ramifications are.
Riley’s protection of cloud-based data for cell phone searches, however, does not address the broader question of whether information stored in the cloud is entitled to Fourth Amendment protection in other contexts. Indeed, the Court went out of its way to state that Riley did ‘not implicate the question [of] whether the collection or inspection of aggregated digital information amounts to a search under other circumstances.’ The Court also distinguished the facts of Riley from those in Smith v. Maryland, one of the principal cases to apply the so-called “third-party doctrine.” The third-party doctrine, which provides that information voluntarily revealed to third parties is not protected by the Fourth Amendment, may pose the biggest obstacle to whether cloud-based data receives Fourth Amendment protection, since any data stored in the cloud is necessarily conveyed to third-party servers. Yet by sidestepping the third-party doctrine in Riley, the Court never had to address how the doctrine applies to private data stored across remote servers.
Nevertheless, while failing to explicitly afford Fourth Amendment protection to cloud-based data, Riley still provides the best evidence yet that the Court may be ready to reconsider the third-party doctrine and to recognize Fourth Amendment protection for personal data stored in the cloud.
— Ryan Watzel, Riley’s Implications for Fourth Amendment Protection in the Cloud, 124 Yale L.J. F. 73 (2014), http://www.yalelawjournal.org/forum/rileys-implications-in-the-cloud.