May 30, 2024

Archives for September 2004

Bike Lock Fiasco

Kryptonite may stymie Superman, but apparently it’s not much of a barrier to bike thieves. Many press reports (e.g., Wired News, New York Times, Boston Globe) say that the supposedly super-strong Kryptonite bike locks can be opened by jamming the empty barrel of a Bic ballpoint pen into the lock and turning clockwise. Understandably, this news has spread like wildfire on the net, especially after someone posted a video of the Bic trick in action. A bike-store employee needed only five seconds to demonstrate the trick for the NYT reporter.

The Kryptonite company is now in a world of hurt. Not only is their reputation severely damaged, but they are on the hook for their anti-theft guarantee, which offers up to $3500 to anybody whose bike is stolen while protected by a Kryptonite lock. The company says it will offer an upgrade program for owners of the now-suspect locks.

As often happens in these sorts of stories, the triggering event was not the discovery of the Bic trick, which had apparently been known for some time among lock-picking geeks, but the diffusion of this knowledge to the general public. The likely tipping point was a mailing list message by Chris Brennan, who had his Kryptonite-protected bike stolen and shortly thereafter heard from a friend about the Bic trick.

I have no direct confirmation that people in the lock-picking community knew this before. All I have is the words of a talking head in the NYT article. [UPDATE (11 AM, Sept. 17): Chris at Mutatron points to a 1992 Usenet message describing a similar technique.] But if it is true that this information was known, then the folks at Kryptonite must have known about it too, which puts their decision to keep selling the locks, and promoting them as the safest thing around, in an even worse light, and quickens the pulses of product liability lawyers.

Whatever the facts turn out to be, this incident seems destined to be Exhibit 1 in the debate over disclosure of security flaws. So far, all we know for sure is that the market will punish Kryptonite for making security claims that turned out to be very wrong.

UPDATE (11:00 AM): The vulnerability here seems to apply to all locks that have the barrel-type lock and key used on most Kryptonite bike locks. It would also apply, for example, to the common Kensington-style laptop locks, and to the locks on some devices such as vending machines.

DRM and the Market

In light of yesterday’s entry on DRM and competition, and the ensuing comment thread, it’s interesting to look at last week’s action by TiVo and ReplayTV to limit their customers’ use of pay-per-view content that the customers have recorded.

If customers buy access to pay-per-view content, and record that content on their TiVo or ReplayTV video recorders, the recorders will now limit playback of that content to a short time period after the recording is made. It’s not clear how the recorders will recognize affected programs, but it seems likely that some kind of signal will be embedded in the programs themselves. If so, this looks a lot like a kind of broadcast-flag technology, applied, ironically, only to programs that consumers have already paid a special fee to receive.

It seems unlikely that TiVo and ReplayTV made the decision to adopt this technology more or less simultaneously. Perhaps there was some kind of agreement between the two companies to take this action together. This kind of agreement, between two companies that together hold most of the personal-video-recorder market, to reduce product functionality in a way that either company, acting alone, would have a competitive disincentive to adopt, seems to raise antitrust issues.

Even so, these are not the only two entries in the market. MythTV, the open-source software replacement, is unlikely to make the same change; so this development will only make MythTV look better to consumers. Perhaps the market will push back, by giving more business to MythTV. True, MythTV is now too hard to for ordinary consumers to use. But if MythTV is as good as people say, it’s only a matter of time before somebody packages up a “MythTV system in a box” product that anybody can buy and use.

Self-Help for Consumers

Braden Cox at Technology Liberation Front writes about a law school symposium on “The Economics of Self-Help and Self-Defense in Cyberspace”. Near the end of an interesting discussion, Cox says this:

The conference ended with Dan Burk at Univ of Minnesota Law School giving a lefty analysis for how DRM will be mostly bad for consumers unless the government steps in and sets limits that preserve fair use. I had to challenge him on this one, and asked where is the market failure here? Consumers will get what they demand, and if some DRM is overly restrictive there will be companies that will provide more to consumers. He said that the consumers of DRM technology are not the general public, but the recording companies, and because society-at-large is not properly represented in this debate the government needs to play a larger role.

I would answer Cox’s question a bit differently. I’m happy to agree with Cox that the market, left to itself, would find a reasonable balance between the desires of media publishers and consumers. But the market hasn’t been left to itself. Congress passed the DMCA, which bans some products that let consumers exercise their rights to make noninfringing use (including fair use) of works.

The best solution would be to repeal the DMCA, or at least to create a real exemption for technologies that enable fair use and other lawful uses. If that’s not possible, and Congress continues to insist on decreeing which media player technologies can exist, the second-best solution is to make those decrees more wisely.

Because of the DMCA, consumers have not gotten what they demand. For example, many consumers demand a DVD player that runs on Linux, but when somebody tried to build one it was deemed illegal.

Perhaps the Technology Liberation Front can help us liberate these technologies.

Security by Obscurity

Adam Shostack points to a new paper by Peter Swire, entitled “A Model for When Disclosure Helps Security”. How, Swire asks, can we reconcile the pro-disclosure “no security by obscurity” stance of crypto weenies with the pro-secrecy, “loose lips sink ships” attitude of the military? Surely both communities understand their own problems; yet they come to different conclusions about the value of secrecy.

Swire argues that the answer lies in the differing characteristics of security problems. For example, when an attacker can cheaply probe a system to learn how it works, secrecy doesn’t help much; but when probing is impossible, expensive, or pointless, secrecy makes more sense.

This is a worthwhile discussion, but I think it slightly misses the point of the “no security by obscurity” principle. The point is not to avoid secrecy altogether; that would almost never be feasible. Instead, the point is to be very careful about what kind of secrecy you rely on.

“Security by obscurity” is really just a perjorative term for systems that violate Kerckhoffs’ Principle, which says that you should not rely on keeping an algorithm secret, but should only rely on keeping a numeric key secret. Keys make better secrets than algorithms do, for at least two reasons. First, it’s easy to use different keys in different times and places, thereby localizing the effect of lost secrets; but it’s hard to vary your algorithms. Second, if keys are generated randomly then we can quantify the effort required for an adversary to guess them; but we can’t predict how hard it will be for an adversary to guess which algorithm we’re using.

So cryptographers do believe in keeping secrets, but are very careful about which kinds of secrets they keep. True, the military’s secrets sometimes violate Kerckhoffs’ principle, but this is mainly because there is no alternative. After all, if you have to get a troopship safely across an ocean, you can’t just encrypt the ship under a secret key and beam it across the water. Your only choice is to rely on keeping the algorithm (i.e., the ship’s route) secret.

In the end, I think there’s less difference between the methods of cryptographers and the military than some people would think. Cryptographers have more options, so they can be pickier about which secrets to keep; but the military has to deal with the options it has.

Absentee Voting Horror Stories

Absentee ballots are a common vector for election fraud, and several U.S. states have inadquate safeguards in their handling, according to a Michael story in today’s New York Times. The story recounts many examples of absentee ballot fraud, including blatant vote-buying.

For in-person voting, polling-place procedures help to authenticate voters and to ensure that votes are cast secretly and are not lost in transit. Absentee voting has weaker safeguards all around. In some states, party workers are even allowed to “help” voters fill out their ballots and to transport completed ballots to election officials. (The latter is problematic because certain ballots might be “lost” in transit.)

Traditional voting security relies on having many eyes in the polling place, watching what happens. Of course, the observers don’t see how each voter votes, but they do see that the vote is cast secretly and by the correct voter. Moving our voting procedures behind closed doors, as with absentee ballots, or inside a technological black box, as with paperless e-voting, undermines these protections.

Without safeguards, absentee ballots are too risky. Even with proper safeguards, they are at best a necessary compromise for voters who genuinely can’t make it to the polls.