When I was working with the Guardian on the Snowden documents, the one top-secret program the NSA desperately did not want us to expose was QUANTUM. This is the NSA's program for what is called packet injection--basically, a technology that allows the agency to hack into computers.
Turns out, though, that the NSA was not alone in its use of this technology. The Chinese government uses packet injection to attack computers. The cyberweapons manufacturer Hacking Team sells packet injection technology to any government willing to pay for it. Criminals use it. And there are hacker tools that give the capability to individuals as well.
All of these existed before I wrote about QUANTUM. By using its knowledge to attack others rather than to build up the internet's defenses, the NSA has worked to ensure that anyone can use packet injection to hack into computers...
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These are the stories you need to keep in mind when thinking about proposals to ensure that all communications systems can be eavesdropped on by government. Both the FBI's James Comey and UK Prime Minister David Cameron recently proposed limiting secure cryptography in favor of cryptography they can have access to.
But here's the problem: technological capabilities cannot distinguish based on morality, nationality, or legality; if the US government is able to use a backdoor in a communications system to spy on its enemies, the Chinese government can use the same backdoor to spy on its dissidents.
Even worse, modern computer technology is inherently democratizing. Today's NSA secrets become tomorrow's PhD theses and the next day's hacker tools. As long as we're all using the same computers, phones, social networking platforms, and computer networks, a vulnerability that allows us to spy also allows us to be spied upon.