Features

net.wars: Bride of Clipper

"It's the Clipper chip," said Ross Anderson, or more or less, "risen out of its grave trailing clanking chains and covered in slime." Anderson was talking about the National Strategy for Trusted Identities in Cyberspace, a plan hatched in the US and announced by cybersecurity czar Howard Schmidt in June.

The Clipper chip was the net.war in progress when I went to my first Computers, Freedom, and Privacy conference, the 1994 edition, held in Chicago. The idea behind Clipper was kind of cute: the government, in the form of the NSA, had devised a cryptographic chip that could be installed in any telecommunications device to encrypt and decrypt any communications it transmitted or received. The catch: the government would retain a master key to allow it to decrypt anything it wanted whenever it felt the need. Privacy advocates and civil libertarians and security experts joined to fight a battle royal against its adoption as a government standard. We'll never know how that would have come out because while passions were still rising a funny thing happened: cryptographer Matt Blaze discovered he could bypass the government's back door (PDF) and use the thing to send really encrypted communications.

End of Clipper chip.

At least, as such.

The most important element of the Clipper chip, however – key escrow – stayed with us a while longer. It means what it sounds like: depositing a copy of your cryptographic key, which is supposed to be kept secret, with an authority. During the 1990s run of fights over key escrow (the US and UK governments wanted it; technical experts, civil libertarians, and privacy advocates all thought it was a terrible idea) such authorities were referred to as "trusted third parties" (TTPs). At one event Privacy International organised to discuss the subject, government representatives made it clear their idea of TTPs were banks. They seemed astonished to discover that in fact people don't trust their banks that much. By the time the UK's Regulation of Investigatory Powers Act was passed in 2000, key escrow had been eliminated.

But it is this very element – TTPs and key escrow – that is clanking along to drip slime on the NSTIC. The proposals are, of course, still quite vague, as the Electronic Frontier Foundation has pointed out. But the proposals do talk of "trusted digital identities" and "identity providers" who may be from the public or private sectors. They talk less, as the Center for Democracy and Technology has pointed out, about the kind of careful user-centric, role-specific, transactional authentication that experts like Jan Camenisch and Stefan Brands have long advocated. (Since I did that 2007 interview with him, Brands' company, Credentica, has been bought by Microsoft and transformed into its new authentication technology, U-Prove.) Have an identity ecosystem, by all means, but the key to winning public trust – the most essential element of any such system – will be ensuring that identity providers are not devised as Medium-sized Brothers-by-proxy.

Blaze said at the time that the Feds were pretty grown-up about the whole thing. Still, I suppose it was predictable that it would reappear. Shortly after the 9/11 attacks Jack Straw, then foreign minister, called those of us who opposed key escrow in the 1990s "very naïve". The rage over that kicked off the first net.wars column

The fact remains that if you're a government and you want access to people's communications and those people encrypt those communications there are only two approaches available to you. One: ban the technology. Two: install systems that let you intercept and decode the communications at will. Both approaches are suddenly vigorously on display with respect to Blackberry devices, which offer the most secure mobile email communications we have (which is why businesses and governments love them so much for their own use).

India wants to take the second approach, but will settle for the first if Research in Motion doesn't install a server in India, where it can be "safely" monitored. The UAE, as everyone heard this week, wants to ban it starting on October 11. (I was on Newsnight Tuesday to talk about this with Kirsty Wark and Alan West.)

No one, not CDT, PI, or EFF, not even me, disputes that there are cases where intercepting and reading communications – wiretapping – is necessary in the interest of protecting innocent lives. But what key escrow and its latter variants enables, as Susan Landau, a security researcher and co-author of Privacy on the Line: The Politics of Wiretapping and Encryption, has noted, is covert wiretapping. Or, choose your own favorite adjective: covert, warrantless, secret, unauthorized, illegal… It would be wonderful to be able to think that all law enforcement heroes are noble, honorable, and incapable of abusing the power we give them. But history says otherwise: where there is no oversight, abuse follows. Judicial oversight of wiretapping requests is our bulwark against mass surveillance.

CDT, EFF, and others are collecting ideas for improving NSTIC, starting with extending the period for public comments, which was distressingly short (are we seeing a pattern develop here?). Go throw some words at the problem.