The NSA wants front door access to your encrypted data

Last December, I had the opportunity to travel to the Netherlands to meet with multiple European tech companies, web hosts, and other infrastructure providers. The topic of intelligence agency backdoors and US corporate involvement with such policies came up more than once, often in not-entirely-friendly ways. Its therefore refreshing to see the head of the NSA, Admiral Michael S. Rogers, state up front that the NSA isnt interested in a backdoor solution to digital surveillance. Instead, he wants a so-called front-door solution which could be even worse.

Instead of handing the NSA a unilateral window into encrypted communications taking place at Google or Apple, Rogers suggested a future in which the encryption keys to access such information would be divided between at least two groups possibly more. In the simplest example, Google would retain half the key, while the NSA held the other half. Thus, the agency wouldnt be able to unilaterally snoop inside anyones files it would need Googles support.

I dont want a back door, Rogers, the director of the nations top electronic spy agency, said during a speech at Princeton University, according to the Washington Post. I want a front door. And I want the front door to have multiple locks. Big locks.

The first problem with Rogers proposed front-door solution is that its a meaningless feel-good measure given the current regulatory structure of our national security system. Before the Snowden leaks, Google, Microsoft, and other digital providers were forbidden from disclosing that theyd received national security letters, even in aggregate. Thanks to Snowden, we now know that Yahoo went to bat for users, challenging the legality and authority of the NSA and lost, every time.

Giving half a key to Google or Yahoo would be meaningless unless the company possesses the authority to refuse to use it. In theory, the court system offers robust oversight of how such capabilities are used. In practice, the FISA court has operated more like a rubber stamp body than an organization devoted to judicial oversight. The government, as a whole, doesnt currently have a great track record of respecting suspects rights the FBI is on record as ordering local police departments to drop cases rather than disclose how secret stingray hardware may have been used in ways that fundamentally violate those suspects Fourth Amendment rights.

The other systemic problem with Rogers suggestion is that it assumes a degree of trust between corporations and government at a time when such good feelings are at an all-time low. The NSA has demonstrated no practical ability to differentiate between friend and foe. Its decision to hoover up data running across Googles transatlantic cables may have been legal, but it illustrated a total lack of respect for Google and a willingness to resort to extrajudicial methods when it was convenient.

The NSA could avoid this problem by sharing the key with government-appointed escrows rather than corporations, but this simply hides the process from public view. Thats already extremely problematic.

The technological problems with the NSAs front-door policy are formidable. The divide the key among trusted parties, approach isnt new the NSA proposed exactly this method of securing its ill-fated Clipper Chip in the early 1990s. At the time, the newly-formed EFF and other consumer advocacy agencies battled the NSAs proposed system, noting that it exposed citizens to increased surveillance while providing no assurance that the cryptographic standard, dubbed Skipjack, was actually secure.

Many of these questions would remain in any escrow system the government dreamed up today. The basic question is, is it possible to design a completely secure system to hold a master key available to the U.S. government but not adversaries, said Donna Dodson, chief cybersecurity adviser at the Commerce Departments National Institute of Standards and Technologies. Theres no way to do this where you dont have unintentional vulnerabilities.

Hackers, generally speaking, dont go after the code itself or attempt to brute-force it instead, they work to compromise the organizations that hold the keys, or find other avenues of attack. Splitting the key into parts is only an advantage if the parts cant be combined or analyzed for clues to the final key structure. In order to function properly, every escrow needs to be secure, and every one-time access key needs to be destroyed.