U.S. Attorney General William Barr gave a talk on Tuesday at Fordham University, on “going dark” and the purported need to outlaw encryption systems that lack backdoors for law-enforcement officials. This was hardly the first time that a Department of Justice official has tried to persuade Americans to accept holes in encryption. What was surprising is that backdoors were the only topic that Barr spoke on: it seems that the Trump administration has become very serious about this issue.
The attorney general’s talk follows a recent line of reasoning that asserts that the Fourth Amendment actually requires that communication providers incorporate encryption backdoors. I’m no lawyer, so I won’t comment on the validity of this theory, except that it seems a remarkable leap to me.
Barr’s speech cites the recent use of WhatsApp groups by Mexican drug cartels, and notes the difficulty that law enforcement is having with these communications. This is surprising, since WhatsApp’s group management is actually one of the weaker parts of that system.
What’s more fascinating is the way the Trump administration’s communication on this issue has evolved. During the tenure of the previous FBI director, James Comey, it was common for law enforcement to focus on access to encrypted physical devices, such as phones. But Barr’s speech turns this focus on its head: the new focus is “data in motion”: text messages and phone calls. Building safe encryption backdoors in these systems is generally considered a much more challenging problem.
A number of elements of Barr’s speech are surprising, and seem to simply misstate the facts. “For example, providers design their products to allow access for software updates using centrally managed security keys. We know of no instance where encryption has been defeated by compromise of those provider-maintained keys,” he says. This is absurd. Theft of software signing keys is in fact extremely common: the Stuxnet malware that attacked Iranian nuclear facilities stole multiple software signing keys. More recently, the Russian NotPetya malware infiltrated Ukraine through a software update mechanism in a popular piece of software.
It is unclear whether Barr is simply unfamiliar with these events, or if he means something entirely different.
Barr’s speech cites three proposals for encryption backdoors that have been made by experts. These include a proposal by Britain’s GCHQ, another by Ray Ozzie, and a third article by Matt Tait. The GCHQ proposal comes from a foreign signals intelligence agency, and is unlikely to work. The Ozzie proposal was made for physical devices like phones, and Tait’s proposal is several years old. None were offered by cryptographers.
Barr also plays down the risk of a technical flaw that might come from such an encryption backdoor: “The real question is whether the residual risk of vulnerability resulting from incorporating a lawful access mechanism is materially greater than those already in the unmodified product.” This is worth some deeper examination as well.
We have precious few examples of legitimate backdoors to reason about. But we do have one illegitimate one: a backdoor that was discovered four years ago in Juniper NetScreen firewalls. The backdoor was based on an NSA algorithm that had been disclosed in the Snowden documents. Remarkably, the source code for Juniper’s firewalls was hijacked by a hacking group, who re-targeted this backdoor for their own purposes.
The ultimate targets and details of the Juniper attack are still not public. The FBI won’t talk about it. There is a good chance that this continued secrecy is hiding one of the more catastrophic breaches in U.S. history. So contrary to Barr’s contention, the risk of encryption backdoors is very real.
And this raises one of the most important points that Barr fails to address. There is no difference between the encryption used by most U.S. government agencies and the encryption we all use. Most government agencies buy their equipment and services “off the shelf.” Even the Office of Personnel Management secured itself using commercial firewalls — NetScreen firewalls, as it happens. The office was famously hacked in 2014, revealing details of virtually every cleared intelligence agent in the country.
What is clear from Barr’s speech is that there is no safe backdoor proposal on the table. He and the administration have nothing new to offer here except for a new interpretation of the Fourth Amendment and a desire to minimize risk. But they do have one thing, and Barr’s speech lays this bare: “I think it is prudent to anticipate that a major incident may well occur at any time that will galvanize public opinion on these issues.”
What they have is time, and the inevitability that given enough of it, something terrible will happen to America. And people, when scared, often don’t make the best decisions. This is why I’m concerned about Mr. Barr’s proposals.