7 ms·

Tracking traveler phones lets Cincinnati airport cut security line wait by third

60 points by cleverjake 12y ago

guelo 12y ago
When iOS 8 came out Apple announced a MAC addresses randomization feature to prevent device scanners like this one. But after people tested the feature it turned out that the scheme only works under a very narrow set of conditions that makes it nearly useless. I haven't heard if this has changed in 8.1 or 8.2 but hopefully Apple will move to stop these shenanigans, as well as Google's Android.
- dublinben 12y ago
  Until that happens, you can prevent this kind of tracking by turning your WiFi radio off. For battery life purposes, it's wise to do this anyway when you're not in a location where you intend to be using the WiFi connection.
  - walterbell 12y ago
    Are there any local-only contextual apps which can turn wifi on or off based on GPS location?
    - ncza 12y ago
      Llama is really nice.
    - cesarb 12y ago
      I like Wi-Fi Matic (https://sites.google.com/site/wifimaticapp/ https://sites.google.com/site/wifimaticapp/). It uses the phone network cell identifiers instead of GPS (so it works even where you can't get a GPS fix), and auto-learns the cell identifiers which can be seen in the range of your wifi networks. And its source code is available (I originally found it on f-droid).
      - shpx 12y ago
        thanks, installed.
- acdha 12y ago
  It doesn't look like MAC randomization is relevant to this scenario unless you're cycling the device on and off the network while you're waiting in line. What it would do is prevent them from tracking you at different locations or trips, although obviously the TSA & airlines still know you were there.
sjm-lbm 12y ago
Probably not helpful, but after reading this I can't stop wanting to make a device that appears to be ~20-30 devices by randomizing its MAC address quickly and causing extra staff to be sent to my line any time I was at a place that used a system like this.
- tedks 12y ago
  You wouldn't need a device, would you? Just a rooted Android phone and an app. Maybe a custom kernel.
- omonra 12y ago
  You're not getting staff directed to your line, you're just screwing with other passengers who are fed erroneous data: "The system allows the airport to display to passengers how long the wait in each of its security lines is." All that system does is show you (ie passenger making decision where to go) which line has fewest people in it.
  - darklajid 12y ago
    "The system allows the airport to display to passengers how long the wait in each of its security lines is. It also allows the airport to adjust its resources to respond to demand." I feel that this supports the GP and contradicts your statement. If you're sure the article is wrong, can you support that?
    - omonra 12y ago
      I guess this is a matter of interpretation. My read is that they simply show accurate line wait expectancy, thus ensuring that all lines are utilized (as opposed to one line being empty and the other having a 10 minute wait). From a business perspective it's much simpler for an airport / TSA to put same staff numbers across and expect passengers to figure out optimal route, as opposed to making staff move around.
  - forrestthewoods 12y ago
    There's nothing erroneous about reporting random mac addresses. I think that should be the default behavior for devices. Mac addresses shouldn't be used for tracking. If the airport reports valid data in an incorrect way that's their fault.
deleted 12y ago
[deleted]
lovemenot 12y ago
A bit surprising that a sufficient proportion of people leave wifi and/or bluetooth services on while at the airport, for this system to get a large enough sample size.
- twblalock 12y ago
  Why would it be surprising? I only turn those off when I get on the plane.
sehugg 12y ago
I can't imagine that tracking cell phone emissions is the simplest way to estimate the number of people in a line. I also can't imagine this is the only thing they are doing/planning to do with the data.
- schoen 12y ago
  Maybe more significantly, they aren't the only ones who are collecting this data. A lot of retailers are doing it, and apparently some governments and others are doing it too, all to keep track of people's whereabouts and habits. There are also people who get in a position to map between a device MAC address and an online identity. The easiest case is people who operate hotspots that make people pay; there are also hotspots where you can authenticate (sometimes optionally) with an account of the hotspot operator's service, which may now include Facebook, not just mobile carriers. In prior mobile OS versions -- at least -- some mobile apps were also directly collecting the wifi MAC address and sending it back to the app developer.
- rasz_pl 12y ago
  It is the cheapest to implement, commodity $4 wifi/bt chip is enough to gather all the data, and you dont even have to process it all that much, 200-400MHz router SoC can do it without external controllers.
softgrow 12y ago
Can't help wondering why they have the "choose the line" step. An obvious improvement is to have one line and direct passengers from the end of the line to the next available station. Then again, a better solution is to staff all screening stations all the time or build more. Why do we wait passengers wait for a minimum wage screening person? By do this we effectively say the passengers time is worth nothing. Their employer might no appreciate them having "idle time" with no-one to screen but I'm sure the passengers would sure like it. We don't mind firefighters and paramedics having down time, this should be extended to airport screeners.
- mistermann 12y ago
  I totally don't understand this, I would presume each line is processing people at 100% (of their capability) - how does controlling what line a person gets into going to shorten aggregate processing time unless some processors are sitting entirely idle, which we all know would never happen.
  - anonymousDan 12y ago
    I'm pretty sure there is some fundamental queueing theory to back this up, as it's the main takeaway I had from a queuing theory course I took in college. Can't remember the details though, so I'm not sure it would still apply if a single queue entailed long walks from the head of the queue to the nearest available 'processor'. EDIT: more background here https://possiblywrong.wordpress.com/2010/12/26/why-multiple-checkout-lines-are-not-all-bad/ https://possiblywrong.wordpress.com/2010/12/26/why-multiple-... It appears you might be right in practice.
    - Dylan16807 12y ago
      I was going to link that too but I realized it had total throughput of cashiers as faster than customers. That means there are idle lines without people switching, which is not realistic at all. I'm really at a loss about what they made faster.
    - mistermann 12y ago
mandeepj 12y ago
> looks for devices over Wi-Fi and Bluetooth There must be lot of devices which are not connected to these two. So, this makes their system not completely accurate. They could have used other options like - 1. Sensors on the floor 2. Sensors on the tables where we put our stuff 3. How busy is x-ray scanner belt? 4. How fast people are getting through scanner door.
- grecy 12y ago
  In all of your suggestions they would have had to pay for the sensors themselves. By using the passenger's phones, they're essentially crowdfunding the cost of the sensors. In both cases, they still have to pay for the "collector and analyzer"
  - mandeepj 12y ago
    Some people may even switch off their phones when they will come to know that they are getting tracked. Another reason for their system's inaccuracy is - not many people use airport wifi. Most of us have data plans.
    - function_seven 12y ago
      > Some people may even switch off their phones when they will come to know that they are getting tracked. They don't need to count each and every person to determine relative wait times, as long as the portion of wifi-enabled travelers is roughly the same in each area. > Another reason for their system's inaccuracy is - not many people use airport wifi. Most of us have data plans. You don't have to be connected to the airport's wifi for this system to work. The phone's wifi radio just has to be turned on.
- ryan-c 12y ago
  For wifi at least, it doesn't have to be connected, the radio just needs to be on.
- rasz_pl 12y ago
  More advanced systems are build around SDR platforms and passively scan GSM band for TMSIs.
imroot 12y ago
I'm wondering if the rapid decrease in the number of flights out of CVG might have also caused the security waits -- since Delta left the Cincinnati airport once the Northwest merger was approved, they keep on cutting flights back...
chrismcb 12y ago
It would be cheaper, easier, and quicker to just do away with security theater completely. Pesto, no wait time at all!
ryguytilidie 12y ago
I don't mean to get all tin foil hatish, but why on earth do they need things like MAC addresses to count how many people are around? Is there not software that could take video of the area and count these people? This just sounds like an excuse to be overbearing...

60 points by cleverjake 12y ago

guelo 12y ago

When iOS 8 came out Apple announced a MAC addresses randomization feature to prevent device scanners like this one. But after people tested the feature it turned out that the scheme only works under a very narrow set of conditions that makes it nearly useless. I haven't heard if this has changed in 8.1 or 8.2 but hopefully Apple will move to stop these shenanigans, as well as Google's Android.

dublinben 12y ago
Until that happens, you can prevent this kind of tracking by turning your WiFi radio off. For battery life purposes, it's wise to do this anyway when you're not in a location where you intend to be using the WiFi connection.
- walterbell 12y ago
  Are there any local-only contextual apps which can turn wifi on or off based on GPS location?
  - ncza 12y ago
    Llama is really nice.
  - cesarb 12y ago
    I like Wi-Fi Matic (https://sites.google.com/site/wifimaticapp/ https://sites.google.com/site/wifimaticapp/). It uses the phone network cell identifiers instead of GPS (so it works even where you can't get a GPS fix), and auto-learns the cell identifiers which can be seen in the range of your wifi networks. And its source code is available (I originally found it on f-droid).
    - shpx 12y ago
      thanks, installed.
acdha 12y ago
It doesn't look like MAC randomization is relevant to this scenario unless you're cycling the device on and off the network while you're waiting in line. What it would do is prevent them from tracking you at different locations or trips, although obviously the TSA & airlines still know you were there.

sjm-lbm 12y ago

Probably not helpful, but after reading this I can't stop wanting to make a device that appears to be ~20-30 devices by randomizing its MAC address quickly and causing extra staff to be sent to my line any time I was at a place that used a system like this.

tedks 12y ago
You wouldn't need a device, would you? Just a rooted Android phone and an app. Maybe a custom kernel.
omonra 12y ago
You're not getting staff directed to your line, you're just screwing with other passengers who are fed erroneous data: "The system allows the airport to display to passengers how long the wait in each of its security lines is." All that system does is show you (ie passenger making decision where to go) which line has fewest people in it.
- darklajid 12y ago
  "The system allows the airport to display to passengers how long the wait in each of its security lines is. It also allows the airport to adjust its resources to respond to demand." I feel that this supports the GP and contradicts your statement. If you're sure the article is wrong, can you support that?
  - omonra 12y ago
    I guess this is a matter of interpretation. My read is that they simply show accurate line wait expectancy, thus ensuring that all lines are utilized (as opposed to one line being empty and the other having a 10 minute wait). From a business perspective it's much simpler for an airport / TSA to put same staff numbers across and expect passengers to figure out optimal route, as opposed to making staff move around.
- forrestthewoods 12y ago
  There's nothing erroneous about reporting random mac addresses. I think that should be the default behavior for devices. Mac addresses shouldn't be used for tracking. If the airport reports valid data in an incorrect way that's their fault.

deleted 12y ago

[deleted]

lovemenot 12y ago

A bit surprising that a sufficient proportion of people leave wifi and/or bluetooth services on while at the airport, for this system to get a large enough sample size.

twblalock 12y ago
Why would it be surprising? I only turn those off when I get on the plane.

sehugg 12y ago

I can't imagine that tracking cell phone emissions is the simplest way to estimate the number of people in a line. I also can't imagine this is the only thing they are doing/planning to do with the data.

schoen 12y ago
Maybe more significantly, they aren't the only ones who are collecting this data. A lot of retailers are doing it, and apparently some governments and others are doing it too, all to keep track of people's whereabouts and habits. There are also people who get in a position to map between a device MAC address and an online identity. The easiest case is people who operate hotspots that make people pay; there are also hotspots where you can authenticate (sometimes optionally) with an account of the hotspot operator's service, which may now include Facebook, not just mobile carriers. In prior mobile OS versions -- at least -- some mobile apps were also directly collecting the wifi MAC address and sending it back to the app developer.
rasz_pl 12y ago
It is the cheapest to implement, commodity $4 wifi/bt chip is enough to gather all the data, and you dont even have to process it all that much, 200-400MHz router SoC can do it without external controllers.

softgrow 12y ago

Can't help wondering why they have the "choose the line" step. An obvious improvement is to have one line and direct passengers from the end of the line to the next available station. Then again, a better solution is to staff all screening stations all the time or build more. Why do we wait passengers wait for a minimum wage screening person? By do this we effectively say the passengers time is worth nothing. Their employer might no appreciate them having "idle time" with no-one to screen but I'm sure the passengers would sure like it. We don't mind firefighters and paramedics having down time, this should be extended to airport screeners.

mistermann 12y ago
I totally don't understand this, I would presume each line is processing people at 100% (of their capability) - how does controlling what line a person gets into going to shorten aggregate processing time unless some processors are sitting entirely idle, which we all know would never happen.
- anonymousDan 12y ago
  I'm pretty sure there is some fundamental queueing theory to back this up, as it's the main takeaway I had from a queuing theory course I took in college. Can't remember the details though, so I'm not sure it would still apply if a single queue entailed long walks from the head of the queue to the nearest available 'processor'. EDIT: more background here https://possiblywrong.wordpress.com/2010/12/26/why-multiple-checkout-lines-are-not-all-bad/ https://possiblywrong.wordpress.com/2010/12/26/why-multiple-... It appears you might be right in practice.
  - Dylan16807 12y ago
    I was going to link that too but I realized it had total throughput of cashiers as faster than customers. That means there are idle lines without people switching, which is not realistic at all. I'm really at a loss about what they made faster.
  - mistermann 12y ago

mandeepj 12y ago

> looks for devices over Wi-Fi and Bluetooth There must be lot of devices which are not connected to these two. So, this makes their system not completely accurate. They could have used other options like - 1. Sensors on the floor 2. Sensors on the tables where we put our stuff 3. How busy is x-ray scanner belt? 4. How fast people are getting through scanner door.

grecy 12y ago
In all of your suggestions they would have had to pay for the sensors themselves. By using the passenger's phones, they're essentially crowdfunding the cost of the sensors. In both cases, they still have to pay for the "collector and analyzer"
- mandeepj 12y ago
  Some people may even switch off their phones when they will come to know that they are getting tracked. Another reason for their system's inaccuracy is - not many people use airport wifi. Most of us have data plans.
  - function_seven 12y ago
    > Some people may even switch off their phones when they will come to know that they are getting tracked. They don't need to count each and every person to determine relative wait times, as long as the portion of wifi-enabled travelers is roughly the same in each area. > Another reason for their system's inaccuracy is - not many people use airport wifi. Most of us have data plans. You don't have to be connected to the airport's wifi for this system to work. The phone's wifi radio just has to be turned on.
ryan-c 12y ago
For wifi at least, it doesn't have to be connected, the radio just needs to be on.
rasz_pl 12y ago
More advanced systems are build around SDR platforms and passively scan GSM band for TMSIs.

imroot 12y ago

I'm wondering if the rapid decrease in the number of flights out of CVG might have also caused the security waits -- since Delta left the Cincinnati airport once the Northwest merger was approved, they keep on cutting flights back...

chrismcb 12y ago

It would be cheaper, easier, and quicker to just do away with security theater completely. Pesto, no wait time at all!

ryguytilidie 12y ago

I don't mean to get all tin foil hatish, but why on earth do they need things like MAC addresses to count how many people are around? Is there not software that could take video of the area and count these people? This just sounds like an excuse to be overbearing...