Defending ourselves from internet-based attacks, internet-originated attacks, is much, much more important than our ability to launch attacks against similar targets in foreign countries.

A zero-day exploit is a method of hacking a system. It's sort of a vulnerability that has an exploit written for it, sort of a key and a lock that go together to a given software package. It could be an internet web server. It could be Microsoft Office. It could be Adobe Reader or it could be Facebook.

When we talk about computer network exploitation, computer network attack, we're not just talking about your home PC. We're talking about your cell phone, and we're also talking about internet routers themselves. The NSA is attacking the critical infrastructure of the internet to try to take ownership of it. They hack the routers that connect nations to the internet itself.

It's clear the CIA was trying to play 'keep away' with documents relevant to an investigation by their overseers in Congress, and that's a serious constitutional concern. But it's equally if not more concerning that we're seeing another 'Merkel Effect,' where an elected official does not care at all that the rights of millions of ordinary citizens are violated by our spies, but suddenly it's a scandal when a politician finds out the same thing happens to them.

When we look at the full-on mass surveillance watching everyone in the country, in the United States, it doesn't work. It didn't stop the attacks in Boston. The marathon bombings. Where again, we knew who these individuals were. It didn't stop the Underwear Bomber, whose father walked into an embassy and warned us about this individual before he walked onto an airplane. And it's not going to stop the next attacks either. Because again, they're not public safety programmes. They're spying programmes. They are valuable for spying.

We decentralise the ability to decide the level of publicity that's attached to any of our communications.

Going all the way back to Daniel Ellsberg, it is clear that the government is not concerned with damage to national security, because in none of these cases was there damage.