Samidh Chakrabarti and Aaron Strauss have written a paper “Carnival Booth: An Algorithm for Defeating the Computer-Assisted Passenger Screening System”. As with any paper, it can be a bit wordy at times, but the majority of it is quite readable. And, with any luck, Declan McCullagh will write-up a summary article in the next few days.
This transparency is the Achilles’ Heel of CAPS; the fact that individuals know their CAPS status enables the system to be reverse engineered. You, like Simonyi, know if you’re carryons have been manually inspected. You know if you’ve been questioned. You know if you’re asked to stand in a special line. You know if you’ve been frisked. All of this open scrutiny makes it possible to learn an anti-profile to defeat CAPS, even if the profile itself is always kept secret. We call this the “Carnival Booth Effect” since, like a carnie, it entices terrorists to “Step Right Up! See if you’re a winner!” In this case, the terrorist can step right up and see if he�s been flagged. […]
Rock.