Thursday, September 22, 2016

The Playpen Story: Some Fourth Amendment Basics and Law Enforcement Hacking

The Playpen Story: Some Fourth Amendment Basics and Law Enforcement Hacking

It’s an old legal adage: bad facts make bad law. And the bad facts present in the Playpen prosecutions—the alleged possession and distribution of child porn, coupled with technology unfamiliar to many judges—have resulted in a number of troubling decisions concerning the Fourth Amendment’s protections in the digital age.

As we discussed in our previous post, courts have struggled to apply traditional rules limiting government searches—specifically, the Fourth Amendment, the Constitution's primary protection against governmental invasions of privacy—to the technology at issue in this case, in some cases finding that the Fourth Amendment offers no protection from government hacking at all. That's a serious problem.

In this post, we’ll do two things: explain the Fourth Amendment “events”—that is, the types of searches and seizures—that take place when the government uses malware, explain how some of the courts considering this issue have gone astray (and some have gotten it right), and what all this means for our digital rights.

Hacks, searches, seizures, and the Fourth Amendment

The Fourth Amendment generally prohibits warrantless law enforcement searches and seizures. A Fourth Amendment “search” occurs when the government intrudes on an area or information in which a person has a reasonable expectation of privacy. A “seizure” occurs when the government substantially interferes with a person's property or their liberty.

As we’ve spelled out in an amicus brief filed in a number of the Playpen prosecutions, when the government hacks into a user’s computer, a series of significant Fourth Amendment searches and seizures occur:

Each use [of the government’s malware] caused three Fourth Amendment events to occur: (1) a seizure of the user’s computer; (2) a search of the private areas of that computer; and (3) a seizure of private information from the computer.

First, the government’s malware “seized” the user’s computer. More specifically, the execution of the government’s code on a user’s device “meaningful[ly] interfered” with the intended operation of the software: it turned a user’s computer into a tool for law enforcement surveillance. By hacking into the user’s device, the government exercised “dominion and control” over the device. And that type of interference and control over a device constitutes a “seizure” for Fourth Amendment purposes.

Next, the government’s code “searched” the device to locate certain specific information from the computer: the MAC address, the operating system running on the computer, and other identifying information. In this instance, where the search occurred is central to the Fourth Amendment analysis: here, the search was carried out on a user’s personal computer, likely located inside their home. Given the wealth of sensitive information on a computer and the historical constitutional protections normally afforded peoples' homes, a personal computer located within the home represents the fundamental core of the Fourth Amendment’s protections.

Finally, the government conducted a “seizure” when its malware copied and sent the information obtained from the user’s device over the internet and back to the FBI. (As an aside, it was sent unencrypted—but more on that in a later blog post about the evidentiary issues arising from these cases.) For its part, the government doesn’t even contest that the copying of this information is a seizure: it described that information as the “information to be seized” in the warrant.

Law enforcement deploying malware against a user in this way should, from a constitutional perspective, be understood the same way as if the search were carried out in the physical world: a police officer physically taking a computer away, looking through it for identifying information, and writing down the information the officer finds for later use. 

Fourth Amendment principles meet digital dissonance

In the physical world, courts would have no problem recognizing the Fourth Amendment consequences of law enforcement physically seizing and searching a computer. Yet, the Playpen cases, and the relatively unfamiliar technology at issue in them, have complicated the application of settled Fourth Amendment law.

Some courts have held that the Fourth Amendment was not implicated by the government’s malware, incorrectly focusing on the information obtained from the search—critically, the IP address—and not how and where the searches and seizures occurred. Those courts have relied on a separate line of cases that held that, when the government obtains an IP address from an ISP or other third party, the user lacks a reasonable expectation of privacy in the IP address, precisely because it was in the hands of a third party.

Even if we agreed with that precedent (generally, we don’t), it has no application to the Playpen cases. The government didn't obtain the IP address and other information from a third party: it got it directly from searching and seizing the user’s device. As one court correctly held:

The government is not permitted to conduct a warrantless search of a place in which a defendant has a reasonable expectation of privacy simply because it intends to seize property for which the defendant does not have a reasonable expectation of privacy. For example, if [the defendant] had written his IP address [] down on a piece of paper and placed it on his desk in his home, the government would not be permitted to conduct a warrantless search of his home to obtain that IP address. The same is true here.

As we wrote before, one court went so far as to say that the defendant had no reasonable expectation of privacy—and, thus, no Fourth Amendment protection—in a personal computer, located within a private home, because it was connected to the Internet. Personal computers inside the home should receive the greatest Fourth Amendment protection, not none at all, so it was deeply concerning to see a judge reach that conclusion.

Essentially, that court held that software vulnerabilities are akin to broken blinds in a person’s house, which allow the government to peer in and see illegal activity—an investigative technique that, although creepy, does not require a warrant. The court held that “Government actors who take advantage of an easily broken system to peer into a user’s computer” are essentially peering in through the digital equivalent of broken blinds.

Setting aside the difference between looking in a window from the street and actively hacking a computer, tying the protections of the Fourth Amendment to the relative strength of security measures sets a dangerous precedent. Many (if not most) physical security features, like a lock on a door, are easily defeated, yet no court would conclude that the government can warrantlessly search a home, simply because the lock could be picked.

What these decisions mean for the law of government hacking

There’s cause for concern about these decisions, but it’s not quite time to panic.

The legal rules that could ultimately flow from decisions, like those described above—that the government may warrantlessly search an electronic device so long as it is only obtaining information that, in other contexts, has been disclosed to a third party; or that the government’s ability to warrantlessly search devices is checked only by their technological capacity to do so—are very bad for privacy, to say the least.

Fortunately, the decisions so far have all been at the district court level. That means that although another court might consider the decision persuasive, the decisions do not establish legal rules that other courts or the government must follow. It will be critically important to watch these cases on appeal, though. Decisions of the federal courts of appeals and the Supreme Court are binding on other courts and the government, so the rules the Playpen cases generate on appeal will create lasting legal rules.

Nevertheless, the cases are still creating a body of troubling decisions in an area that, until now, was relatively lightly covered in the federal courts, creating a kind of bedrock layer of precedent for government hacking. Before the Playpen prosecutions, only a handful of decisions involving government hacking existed; when these cases are all said and done, there may be a hundred. That makes it all the more critical that we get these cases right—and set the right limits on government hacking—at the outset.

Source: The Playpen Story: Some Fourth Amendment Basics and Law Enforcement Hacking | Electronic Frontier Foundation