I do this infrequently, but this topic is so apropos to the previous post that I thought it worth reposting in its entirety. I'd point out the unbelievable prescience shown in the dawn of this blog (only 100 days old at the time - still had that New Blog smell!), but it's really kind of obvious, isn't it?
One of the biggest problems in Internet Security is getting the "False
Positive" rate down to a manageable level. A False Positive is an event
where your security device reports an attack, where there's no actual
attack happening. It's the Boy Who Cried Wolf
problem, and if it's too high, people turn the security off.
Apple had a hilarious ad that spoofed Vista's UAC
security a while back. The security is so good that the whole system is unusable:
Surprise! Seems that identifying terrorists by mining a bunch of databases isn't any better
report scheduled to be released on Tuesday by the National Research
Council, which has been years in the making, concludes that automated
identification of terrorists through data mining or any other mechanism
'is neither feasible as an objective nor desirable as a goal of
technology development efforts.' Inevitable false positives will result
in 'ordinary, law-abiding citizens and businesses' being incorrectly
flagged as suspects. The whopping 352-page report, called 'Protecting
Individual Privacy in the Struggle Against Terrorists,' amounts to [be]
at least a partial repudiation of the Defense Department's controversial
data-mining program called Total Information Awareness, which was
limited by Congress in 2003.
The problem is not so much one
of technology, as it is of cost. Suppose you could create system where
the data mining results gave you only one chance in a million at false
positive. In other words, for every person identified as a potential
terrorist, you were 99.9999% likely to be correct. This is almost
certainly 3 or 4 orders of magnitude overly optimistic (the actual
chances are likely no better than 1 in a thousand, and may well be much
less), but let's ignore that.
There are roughly 700 Million air passengers
in the US each year. One chance in a million means the system would
report 700 likely terrorists (remember, this thought experiment assumes a
ridiculously low false positive rate). The question, now, is what do you do with these 700 people
Right now, we don't do anything, other than not let them fly. If they're Senator Kennedy, they make a fuss at budget time, and someone takes them off the list
; otherwise, we don't do anything. So all this fuss, and nothing really happens? How come?
If we really thought these folks were actually terrorists, we'd
investigate them. A reasonable investigation involves a lot of effort -
wire taps (first, get a warrant), stakeouts, careful collection of a
case by Law Enforcement, prosecution. Probably a million dollars between
police, lawyers, courts, etc - probably a lot more, if there's a trial.
of the 700. We're looking at a billion dollars, and this assumes a ridiculously low false positive rate.
There are on the order of a hundred thousand people
in TSA's no-fly or watch databases. Not 700. If you investigated them all, you're talking a hundred billion
bucks. So they turn the system off.
that's actually the right answer. The data's lousy, joining lousy data
with more lousy data makes the results lousier, and it's too expensive
to make it work. How lousy is the data? Sky Marshals
are on the No-Fly list. No, really
. 5 year olds
So the Fed.Gov sweeps it under the rug, thanks everyone involved for all their hard work, and pushes the "off" button.
As expected, the Slashdot comments are all over this
take their "no fly" list and identify every single person on it who was
a legitimate threat and either have them under 24 hour surveillance or
The mere concept of a list of names of people who are too "dangerous" to let fly ... but not dangerous enough to track ... that just [censored - ed] stupid.
At least everyone's looking busy. The analogies to gun control pretty much write themselves.