An opensource alternative for the TSA’s $300k line assistant (opens in new tab)

I know not all engineers do this, but this crap is what caused me to buy a new laptop. I was fine with my existing tools and workflow, but websites have gotten so slow and ridiculous. It's largely Javascript's fault.

I used to get angry about walled garden app stores, but lately I find myself hating the web. I don't dislike it, but I think we went on a really lame detour.

As an aside, Javascript ads are worse than Flash ads ever were.

I admit to thinking the dependency overkill for random arrows was part the joke. A la https://github.com/jezen/is-thirteen

http://bettermotherfuckingwebsite.com/

Let's say you have a mobile app used by 1 billion people every day. It sounds crazy, but I bet a fair number of people in this forum contribute to such an application.

Imagine you want to make an optimization that increases battery life by 1%. Assume a 30Wh battery and that it's charged once per day. Over the two year lifetime of the phone, at $0.10 per KWh, that change would save your users 21.9 million dollars in aggregate. Even with a team of 40 people making $500,000 per year working for a year, you still increase the efficiency of society with that change!

(I know, this ignores the opportunity cost of adding a new feature before your competitor, or focusing on something that will bring more user happiness, or the externality that users don't notice the $0.00003 they're paying to supply your app with electricity. But the point is, we have a lot of power, and our time is much cheaper when multiplied proportionally to that impact.)

There are roughly 100k commercial flights per day, 36m flights per year.

Therefore, the probability of your flight being hijacked is 1 in 30 million, which is an absurdly low number. Note that only one of the 6 hijackings resulted in casualties, so the mortality rate even lower.

That said, 47k still seems crazy high. I've never done Gov't consulting though. One hopes hardware was included in the contract?

Not really. If you were flipping the penny to get heads or tails and lost it, you could easily replace that penny with a coin, a washer, a stick from outside, a book...hundreds of things already around your home or office, many with no use or value. You can't look around you and find a replacement for the penny as a currency.

Very big change in cost, considering the actual price of the TSA app.

Specifically, if you're talking about ciphers (as Kerckhoffs does), or system software (as NIST does), or anything else, you know in advance who's authorized and who's not. You've solved the hard problem; the rest is simply math, and we're fortunate to live in a time where the math is well-studied. You can give the secret key to the people who are authorized, and not to those who aren't, and your security rests on that key -- and your competence at figuring out who should have been given the key.

The TSA has no such luxury. They have no good way to distinguish me, a random person walking through the airport with a valid boarding pass and too many electronics, from a terrorist, also with a valid boarding pass and many electronics. If they could give me a key in advance, and not the terrorist, they would. (In fact, this is basically what Pre-Check is, and that works okay, although it only reduces the screening because they know Pre-Check can't be perfect.) But there's nothing that reliably distinguishes me and you and hundreds of millions of other non-terrorists from the small number of terrorists, and there's certainly no practical way to publish a key to us hundreds of millions, while keeping it away from terrorists.

So they rely on heuristics, because there is no better option. You cannot build a system that satisfies Kerckhoff's principle, because there is no key separate from the system itself. And any public, keyless system can be gamed trivially. (Think of, say, unkeyed SHA-256 checksums attesting to software integrity. Without a signature, i.e., without a key, anyone can tamper with both the software and the checksum, regardless of how good SHA-256 is.) So the system must be kept private in order for it to work at all... or we give up, and decide that the only people who can fly are those that we can conduct foolproof background checks on. That seems like a worse world.

It is rather like anti-spam and anti-virus. If you could just give a key to all legitimate email or legitimate software, you would. And in fact there are things that attempt to do that. But they can't be complete, and the remainder of the screening works on security-by-obscurity because there is no better option. Either we give up entirely on the ability to receive unsigned mail or run unsigned software (and even that won't be 100% reliable), or we go with the secret heuristics. It's not great, but it's the best we can do.