8 ms·

How does Apple privately find offline devices?

347 points by kandarpck 7y ago

SlowRobotAhead 7y ago
>can use a single [private] key regardless of which randomized version of her public key was used to encrypt. I have not seen this before. Trying to wrap my brain around how this works. In terms of ECC I thought public and private were a single pair. Can anyone explain what is going on with public key randomization?
- philipkiely 7y ago
  Warning: this is baseless speculation from someone with only a semester of cryptography experience. If you asked me to implement "randomized public keys" I would generate a master key pair (MPUB and MPRIV). Then, I would combine MPRIV and a random value N in a one-way function to make a new key K. I would use K as effectively a "random public key" and use it as if it was MPUB (the one-way function would have to output a K that is in the same format / usable like MPUB). I would distribute N along with K, as N is useless without MPRIV. I have no idea if that is how they did it but that's what comes to mind.
  - ryanmarsh 7y ago
    Warning, no academic crypto experience but I've used it in production systems. Oh the horror. Couldn't "random value N" just be a nonce that only Apple knows?
- Scaevolus 7y ago
  You can derive a new public key from someone's ECC public key, and they can derive the corresponding private key by applying the same transformation. It's somewhat magical! I wouldn't be surprised if Apple is using a scheme based on this instead of ElGamal, they already use ECC extensively. https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#conventions https://github.com/bitcoin/bips/blob/master/bip-0032.mediawi...
  - snarf21 7y ago
    Interesting, I hadn't thought of using the techniques of deterministic cryptocurrency wallets to solve this problem. I need to read more about exactly how they work. It is also easy to solve this simply using ECC and ECDH. I just wrote a scheme on the board in the office. It might have slightly larger data payload than the deterministic wallets approach.
- xvector 7y ago
  The article gives the example of El Gamal encryption [1]. Looking at the key generation section, it seems like you could keep a single (q, x) pair and create a new (G, g, h) for the same x.
- Too 7y ago
  Just speculating but would something like random_key=hash(static_key + datetime) work? static_key is pre-shared between cloud and device and datetime is also known by both device and cloud if rounded down to some accuracy.
kohtatsu 7y ago
The post is speculation; perhaps s/does/might/ or s/does/could/ in the title.
- pwinnski 7y ago
  Not so much; most of the article restates in simpler terms what Apple has outlined as reported in Wired[0]. [0] https://www.wired.com/story/apple-find-my-cryptography-bluetooth/ https://www.wired.com/story/apple-find-my-cryptography-bluet...
- Fnoord 7y ago
  The title is a question. Which is why it ends with a questionmark. The article attempts to answer the question with theories. The article isn't written by Joe Random; it is written by Matthew Green who teaches cryptography at John Hopkins university.
  - helper 7y ago
    Johns* Hopkins.
m463 7y ago
Can we turn this off? please? I would like 100% passive bluetooth. (and wifi, and nfc)
- Xylakant 7y ago
  How is that going to work? All communication that you initiate must be active. The only passive option would be broadcasts like TV or radio stations, but that’s not particularly useful if you want to view a specific website.
  - berbec 7y ago
    NFC is passive until powered by an external signal. It's very short range, but it does not require internal power. There could be a longer range version at some point.
    - RosanaAnaDana 7y ago
      Maybe thats what this is. I'm well outside of the world of signal transduction, but a cell antenna/ wifi/ bluetooth antenna might be able to..
    - Xylakant 7y ago
      Yes, but an NFC tag cannot initiate a connection on its own volition. And that’s very much a feature I like in WiFi: I can actively start downloading something. A WiFi card that only responds to an external ping is useless.
      - m463 7y ago
        I think what berbec is saying is maybe you can locate an NFC device that has a depleted battery. That said, I don't know if apple NFC works that way. Apple can use NFC to read nearby NFC tags, and possibly become an NFC tag, but I don't know if it can respond in a static way without power.
  - RosanaAnaDana 7y ago
ShakataGaNai 7y ago
The problem I see with this is that your phone always has to be broadcasting the BLE beacon, regardless of if it is lost or not. Otherwise it could randomly end up lost in a place with poor/no service... and would never be found For phones, how often is this really an issue? Sure, this is useful for the Tile type "dumb" devices... but if my phone has no cell or data service... it's probably because the battery is dead.
- Uehreka 7y ago
  Some people have hypothesized that this isn't necessarily for finding phones. This might be about using phones (and iPads, Apple Watches, MacBooks, etc.) to create a network like the one used by the Tile product for finding wallets, keys, etc. This could be a product Apple unveils in September.
  - m0dest 7y ago
    This is for tracking lost MacBooks. Apple said this at the keynote. They may expand it beyond laptops, but that's the initial scenario. (It's a great one.)
- Slippery_John 7y ago
  I can think of several scenarios: * I lost the phone hiking somewhere with no signal * I lost the phone / it was stolen while in airplane mode * I lost the phone while traveling abroad without any local service This finding service will work for wifi-only ipads, wifi-only apple watches, and macbooks in addition to the likely tracking tokens.
  - Fnoord 7y ago
    Stolen while in airplane mode, and you're going to rely on BLE? A "good" thief would learn that he'd need to carry around a Faraday cage (read: some tinfoil) to block the signals. The only disadvantage is that the act of putting tinfoil around an iPhone then becomes suspicious.
    - 7y ago
RIMR 7y ago
Okay, so this would make it insanely easy to stalk any iPhone user. 1. Get BLE tracking tags, and register them with Find My. 2. Covertly attach the BLE tracking tags to things your target owns (backpacks, cars, bikes, etc). 3. You constantly get updates on your tags locations via their iPhone and other iOS devices near the BLE tag(s). This gives you their approximate location and movement history, facilitated primarily through their own iPhone and data plan.
- dmitrygr 7y ago
  I have no idea how the FindMy BLE system works, but i strongly suspect that the cheaperst compatible "tag" you will find will be an iPhone. Might get a tad expensive to do this...
  - bdcravens 7y ago
    The potential of low cost tags is in the first paragraph, and an overview of how the system would work is in the second. My takeaway is that you will be able to use something far cheaper than an iPhone.
    - dmitrygr 7y ago
      Cheap ble tags do NOT use fancy rotated private keys or anything of the like. At best they use BLE privacy mode. That is as private as the spec gets. Source: worked on Bluetooth for years
  - judge2020 7y ago
    Assuming the newest ipod touches will work with this, $200 is the cheapest you could do this with in terms of using an iOS device (not that i'm suggesting this is a great option. As pointed out by the other second-level comments, you could just use tile or a real gps tracker without needing iOS).
- pwinnski 7y ago
  The only "BLE tracking tags" reported to use Find My are Apple devices, and if you can attach an Apple device to something your target owns, there are many means you can use other than Find My to track them. I mean, if you can accomplish step 2, you don't need Apple at all.
imhoguy 7y ago
I see lots of poor Lassies in airports, conferencies and generally in crowded places. Not even mentioning flood or replay attacks. Lassie's help needs to have some limits otherwise it may quickly drain batteries or mobile plans especially in roaming.
- stouset 7y ago
  BLE is insanely battery-efficient. And in most scenarios with a lost device, it's either stationary or will be stationary for a sufficient period of time to be discovered, so a ping only once every hour is probably more than enough to locate it. Or a ping with exponential backoff as battery depletes. Sending the locations from these pings likewise also uses negligible battery, as Apple already coalesces timers and network traffic like push notifications. I don't understand the mentality where people think Apple would have announced this without doing any testing on its battery life impact.
  - photojosh 7y ago
    Yep. I have a BLE speed sensor on my bike which runs off a CR2032 coin cell. It's been two years of daily commuting and I've yet to change the battery.
- saagarjha 7y ago
  It's Bluetooth Low Energy, though. Should last for quite a while?
- randyrand 7y ago
  "Apple's recommended setting of 100 ms advertising interval with a coin cell battery provides for 1–3 months of life, which increases to 2–3 years as advertising interval is increased to 900 ms." iPhone's have about at 10X larger batter than that. So iPhones can do this for ~20-30 years if configured correctly.
  - ryanmarsh 7y ago
    If I'm not mistaken the normal self-discharge rate for a phone's lithium ion battery will exceed the maintenance of BLE advertisement.
RosanaAnaDana 7y ago
Total aside, but kinda relevant. I lost my phone like a dufus about a two weeks ago. Battery died and I had no idea where it was. When I pulled the my google location history, it was too coarse to tell me anything other than 'at your house'. However, I was able to pull the raw data from google and post process it by time stamp into a series of rasters that were fine enough for me to see that the phone was definitely in the bedroom/ bathroom area. After processing my data, finding my phone took all of a minute.
- mehrdadn 7y ago
  This is interesting. By the raw data you mean from Google Takeout, or something else? Did you have to filter/smooth the data points?
  - machinesmachine 7y ago
    Also interested. Could you describe the process?
    - RosanaAnaDana 7y ago
      Sure. I pulled my data in the standard takeout.google.com/ process. The result is a json (? iirc). I parsed the json into x, y, and rasterized it using gdal. https://imgur.com/a/ZhyTsDV https://imgur.com/a/ZhyTsDV See I wasn't sure if I lost it in the couch in the living room, the office, or the bedroom. This got me within a few feet.
      - icelancer 7y ago
        Ha, this is an awesome use of the data. What a cool plot showing the "density" of pings.
      - crazygringo 7y ago
        That's amazing, so cool. Is that something Google's not doing with the data, but could? (E.g. they don't because their maps don't show most houses precisely enough or whatever, so it wouldn't be useful?) Or is it relying on the fact that you are triangulating or similar from the known exact position of your WiFi routers or similar down to the inch, and Google doesn't have any way of knowing that?
JohnFen 7y ago
> The good news is that Apple claims that their system actually does provide strong privacy, and that it accomplishes this using clever cryptography. But that does nothing to protect your privacy against Apple. I already have to make sure that I disable WiFi and Bluetooth when I enter commercial establishments. Now I have to stop using Bluetooth whenever I leave my house?
- berbec 7y ago
  It gets worse: if you turn off wifi/bluetooth in control center, it only disconnects, keeping the radio active. 1: https://support.apple.com/en-us/HT208086 https://support.apple.com/en-us/HT208086
  - judge2020 7y ago
    As it says on the page, this is to make sure a bunch of things still work (eg. you wouldn't really thing you need to keep Bluetooth enabled to use the pencil). Maybe the toast text "disconnecting nearby Wi-Fi until tomorrow" could be a little clearer.
    - sixstringtheory 7y ago
      From day one I’ve wanted a way to disable the automatic-reenabling feature.
      - jey 7y ago
        Use airplane mode then enable each one individually?
  - deleted 7y ago
    [deleted]
  - SHAKEDECADE 7y ago
    You can use shortcuts to disable and enable things. I use one labled ‘Car’ that turns off wifi, enables cellular data and BLT for the stereo and terminates after it ensures my (non-DNS) VPN is on. The other, ‘Home’ turns off cellular data and BLT, wifi on and again ensures my VPN is still active. Also if you’ve got anything newer than a iPhone 6, you can 3D touch the settings icon to a pop-up menu to Bluetooth, Wi-Fi, Cellular Data and the Battery sub-menus. From there it’s an extra tap or two to disable stuff completely. Formatting is likely terrible, I mobile-phoned this in..
crazygringo 7y ago
Can this be used as essentially 100% effective anti-theft? If an Apple device is constantly emitting a BLE beacon code that can't effectively be changed in any way by a thief... ...then unless a thief keeps the device in their basement and never has anybody visit, your stolen device will almost certainly be detected sooner or later, and then you just call the police? Even if the thief has sold it by that point and disappeared, if local law means the stolen good reverts to you, then people would quickly learn never to purchase any phone there's even a chance of having been suspiciously acquired. Am I missing something here?
- tinymint 7y ago
  Not 100% effective - device could still be stolen and parted out
  - SmellyGeekBoy 7y ago
    If only Apple would sell spares through official channels, it would reduce the incentive to steal iPhones even further.
- kccqzy 7y ago
  Thieves already know that stolen iPhones are usually not operable. Even with the old Find My iPhone, even after the device has been wiped, only the original owner can activate it again. So these stolen phones are usually broken down, with parts sold separately.
  - president 7y ago
    They are getting smarter. A family member had their phone stolen and Find My iPhone reported that the phone was off for months and so she gave up searching. One day, she got a text on her new phone saying "Find my iPhone has found your phone, click here to login to Find my iPhone". It turned out to be a phishing page for her AppleID credentials. She fell for it and I'm assuming the thieves were able to finally get into her phone. To this day I have no idea how they were able to get her phone number. From the SIM maybe?
freen 7y ago
This sounds like the perfect infrastructure for a trusted, encrypted P2P mesh network.
ryanmarsh 7y ago
I designed a similar system a few years back to provide proof-of-presence. Imagine a block chain of devices at locations (an alibi lets say). All devices are miners and only devices in your vicinity (think BLE) can "confirm" "transactions" (your presence) on the chain. As with anything public + blockchain it had all the Cryptoeconomics incentives problems you would expect and I never solved them. Finding a lost device has much lower stakes than proving an alibi in court so I see how this model would work.
zed88 7y ago
Well...a bit off topic but kind of relevant. My car got broken into and my iPad nicked. I was able to locate that, however, the cops here in NZ were really unhelpful. They said the GPS location wouldn't be sufficient for a search warrant as they have had many cases of false positives. I said I would give the ssid and ip address of their wifi network, even then they wouldn't agree for a raid. It was only when the thief (who was a minor) took the pic of his family member, which I then furnished to the police (via iCloud), they could do something. Wondering what good is technology, if the law takes a while to catchup, well at least here in NZ.
- dylan604 7y ago
  It's not just NZ. Police in the US are no better. In the Dallas PD, the detective assigned to the case when our house was burgled would not respond to emails sent to him providing evidence. After reaching out through other avenues to reach the detective, he flat out responded with being too busy to read emails. The case went uncleared. However, a few weeks later, there was a random call saying they found an iPad reported as lost/stolen and would be willing to return it for a small finder's fee. Again, the police refused to assist during the meet up.
  - m463 7y ago
    I've noticed in my lifetime that a number of crimes have become ad-hoc decriminalized. Smaller crimes like bicycle theft or small electronics are basically "who cares" to the police. Many police departments don't even do bicycle registrations anymore. Even car theft has sort of fallen to insurance companies to take care of. A lot of people just want a police report to turn in to insurance so they can get a new car. I don't know about serious crimes. Are people more often caught with lots of data and the erosion of privacy?
    - Cthulhu_ 7y ago
      I'm sure they prefer to focus on bigger cases - why go with a single bike theft if they can investigate an organized bike theft and laundering organization? Why bother with a single phone theft if they find a warehouse full of stolen merchandise? But yeah, that does mean a lot of petty crime goes unpunished. Stealing a bike here has become normalized - as in, "my bike got stolen, I need to get home so I'll just steal another". Mind you that's only possible with shoddy locks.
zone411 7y ago
Tile has quite a few patents in this area: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=0&f=S&l=50&TERM1=tile&FIELD1=ASNM&co1=AND&TERM2=&FIELD2=&d=PTXT http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=H...
sebazzz 7y ago
Can the signal be jammed? Or simply put the stolen device in a metal box. As for the tracking: I really like the idea. However, in my country finding your device isn't the issue, it is getting it back that's the problem. Police won't go and enter the particular house were your device is.
- ascorbic 7y ago
  I'm not sure how useful a device is that has to be kept in a metal box at all times.
  - justwalt 7y ago
    My new startup: Faraday gloves
antpls 7y ago
Nice article, and also nice application of cryptography. I hope Google and Apple will both compete and challenge each others about inventive ways to defend people privacy, both at the hardware and software levels
Skunkleton 7y ago
> generate the list of pseudonyms from a single short “seed” that both Timmy and Ruth will keep a copy of. This is nice because the data stored by each party will be very small. However, to find Timmy, Ruth must still send all of the pseudonyms — or her “seed” — up to Apple, who will have to search its database for each one. I would imagine something along the lines of TOTP would provide a better mechanism here. There would be no need to scan a whole list of pseudonyms, and the BLE would rotate the identifier it transmits frequently. The lassie device can include GPS timestamps when it reports the device to apple.
mjlee 7y ago
A potential concern - does this system implement forward secrecy? Is that even possible? The threat I'm thinking of is some organisation that is able to crack the private key at some point in the future and therefore able to work out where you have been in the past. Of course, the phone's location in the recent past is exactly what this system is designed to produce. Would it be possible to rekey the connection on a regular/opportunistic basis?
shitals 7y ago
TLDR; The idea of the new system is to turn Apple’s existing network of iPhones into a massive crowdsourced location tracking system. Every active iPhone will continuously monitor for BLE beacon messages that might be coming from a lost device. When it picks up one of these signals, the participating phone tags the data with its own current GPS location; then it sends the whole package up to Apple’s servers.
graton 7y ago
Milwaukee Tools (and possibly others) do something similar. Not sure about the privacy part though. https://www.milwaukeetool.com/OneKey https://www.milwaukeetool.com/OneKey Basically anyone who runs the Milwaukee One Key app will watch for signals from tools and other devices with the One Key transmitter and upload the location. So if your tool is stolen and comes within range of someone running the One Key app the location should get uploaded.
- snarf21 7y ago
  Tile meshes the same way.
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347 points by kandarpck 7y ago

>can use a single [private] key regardless of which randomized version of her public key was used to encrypt. I have not seen this before. Trying to wrap my brain around how this works. In terms of ECC I thought public and private were a single pair. Can anyone explain what is going on with public key randomization?

philipkiely 7y ago
Warning: this is baseless speculation from someone with only a semester of cryptography experience. If you asked me to implement "randomized public keys" I would generate a master key pair (MPUB and MPRIV). Then, I would combine MPRIV and a random value N in a one-way function to make a new key K. I would use K as effectively a "random public key" and use it as if it was MPUB (the one-way function would have to output a K that is in the same format / usable like MPUB). I would distribute N along with K, as N is useless without MPRIV. I have no idea if that is how they did it but that's what comes to mind.
- ryanmarsh 7y ago
  Warning, no academic crypto experience but I've used it in production systems. Oh the horror. Couldn't "random value N" just be a nonce that only Apple knows?
Scaevolus 7y ago
You can derive a new public key from someone's ECC public key, and they can derive the corresponding private key by applying the same transformation. It's somewhat magical! I wouldn't be surprised if Apple is using a scheme based on this instead of ElGamal, they already use ECC extensively. https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#conventions https://github.com/bitcoin/bips/blob/master/bip-0032.mediawi...
- snarf21 7y ago
  Interesting, I hadn't thought of using the techniques of deterministic cryptocurrency wallets to solve this problem. I need to read more about exactly how they work. It is also easy to solve this simply using ECC and ECDH. I just wrote a scheme on the board in the office. It might have slightly larger data payload than the deterministic wallets approach.
xvector 7y ago
The article gives the example of El Gamal encryption [1]. Looking at the key generation section, it seems like you could keep a single (q, x) pair and create a new (G, g, h) for the same x.
Too 7y ago
Just speculating but would something like random_key=hash(static_key + datetime) work? static_key is pre-shared between cloud and device and datetime is also known by both device and cloud if rounded down to some accuracy.

kohtatsu 7y ago

The post is speculation; perhaps s/does/might/ or s/does/could/ in the title.

pwinnski 7y ago
Not so much; most of the article restates in simpler terms what Apple has outlined as reported in Wired[0]. [0] https://www.wired.com/story/apple-find-my-cryptography-bluetooth/ https://www.wired.com/story/apple-find-my-cryptography-bluet...
Fnoord 7y ago
The title is a question. Which is why it ends with a questionmark. The article attempts to answer the question with theories. The article isn't written by Joe Random; it is written by Matthew Green who teaches cryptography at John Hopkins university.
- helper 7y ago
  Johns* Hopkins.

m463 7y ago

Can we turn this off? please? I would like 100% passive bluetooth. (and wifi, and nfc)

Xylakant 7y ago
How is that going to work? All communication that you initiate must be active. The only passive option would be broadcasts like TV or radio stations, but that’s not particularly useful if you want to view a specific website.
- berbec 7y ago
  NFC is passive until powered by an external signal. It's very short range, but it does not require internal power. There could be a longer range version at some point.
  - RosanaAnaDana 7y ago
    Maybe thats what this is. I'm well outside of the world of signal transduction, but a cell antenna/ wifi/ bluetooth antenna might be able to..
  - Xylakant 7y ago
    Yes, but an NFC tag cannot initiate a connection on its own volition. And that’s very much a feature I like in WiFi: I can actively start downloading something. A WiFi card that only responds to an external ping is useless.
    - m463 7y ago
      I think what berbec is saying is maybe you can locate an NFC device that has a depleted battery. That said, I don't know if apple NFC works that way. Apple can use NFC to read nearby NFC tags, and possibly become an NFC tag, but I don't know if it can respond in a static way without power.
- RosanaAnaDana 7y ago

ShakataGaNai 7y ago

The problem I see with this is that your phone always has to be broadcasting the BLE beacon, regardless of if it is lost or not. Otherwise it could randomly end up lost in a place with poor/no service... and would never be found For phones, how often is this really an issue? Sure, this is useful for the Tile type "dumb" devices... but if my phone has no cell or data service... it's probably because the battery is dead.

Uehreka 7y ago
Some people have hypothesized that this isn't necessarily for finding phones. This might be about using phones (and iPads, Apple Watches, MacBooks, etc.) to create a network like the one used by the Tile product for finding wallets, keys, etc. This could be a product Apple unveils in September.
- m0dest 7y ago
  This is for tracking lost MacBooks. Apple said this at the keynote. They may expand it beyond laptops, but that's the initial scenario. (It's a great one.)
Slippery_John 7y ago
I can think of several scenarios: * I lost the phone hiking somewhere with no signal * I lost the phone / it was stolen while in airplane mode * I lost the phone while traveling abroad without any local service This finding service will work for wifi-only ipads, wifi-only apple watches, and macbooks in addition to the likely tracking tokens.
- Fnoord 7y ago
  Stolen while in airplane mode, and you're going to rely on BLE? A "good" thief would learn that he'd need to carry around a Faraday cage (read: some tinfoil) to block the signals. The only disadvantage is that the act of putting tinfoil around an iPhone then becomes suspicious.
  - 7y ago

RIMR 7y ago

Okay, so this would make it insanely easy to stalk any iPhone user. 1. Get BLE tracking tags, and register them with Find My. 2. Covertly attach the BLE tracking tags to things your target owns (backpacks, cars, bikes, etc). 3. You constantly get updates on your tags locations via their iPhone and other iOS devices near the BLE tag(s). This gives you their approximate location and movement history, facilitated primarily through their own iPhone and data plan.

dmitrygr 7y ago
I have no idea how the FindMy BLE system works, but i strongly suspect that the cheaperst compatible "tag" you will find will be an iPhone. Might get a tad expensive to do this...
- bdcravens 7y ago
  The potential of low cost tags is in the first paragraph, and an overview of how the system would work is in the second. My takeaway is that you will be able to use something far cheaper than an iPhone.
  - dmitrygr 7y ago
    Cheap ble tags do NOT use fancy rotated private keys or anything of the like. At best they use BLE privacy mode. That is as private as the spec gets. Source: worked on Bluetooth for years
- judge2020 7y ago
  Assuming the newest ipod touches will work with this, $200 is the cheapest you could do this with in terms of using an iOS device (not that i'm suggesting this is a great option. As pointed out by the other second-level comments, you could just use tile or a real gps tracker without needing iOS).
pwinnski 7y ago
The only "BLE tracking tags" reported to use Find My are Apple devices, and if you can attach an Apple device to something your target owns, there are many means you can use other than Find My to track them. I mean, if you can accomplish step 2, you don't need Apple at all.

imhoguy 7y ago

I see lots of poor Lassies in airports, conferencies and generally in crowded places. Not even mentioning flood or replay attacks. Lassie's help needs to have some limits otherwise it may quickly drain batteries or mobile plans especially in roaming.

stouset 7y ago
BLE is insanely battery-efficient. And in most scenarios with a lost device, it's either stationary or will be stationary for a sufficient period of time to be discovered, so a ping only once every hour is probably more than enough to locate it. Or a ping with exponential backoff as battery depletes. Sending the locations from these pings likewise also uses negligible battery, as Apple already coalesces timers and network traffic like push notifications. I don't understand the mentality where people think Apple would have announced this without doing any testing on its battery life impact.
- photojosh 7y ago
  Yep. I have a BLE speed sensor on my bike which runs off a CR2032 coin cell. It's been two years of daily commuting and I've yet to change the battery.
saagarjha 7y ago
It's Bluetooth Low Energy, though. Should last for quite a while?
randyrand 7y ago
"Apple's recommended setting of 100 ms advertising interval with a coin cell battery provides for 1–3 months of life, which increases to 2–3 years as advertising interval is increased to 900 ms." iPhone's have about at 10X larger batter than that. So iPhones can do this for ~20-30 years if configured correctly.
- ryanmarsh 7y ago
  If I'm not mistaken the normal self-discharge rate for a phone's lithium ion battery will exceed the maintenance of BLE advertisement.

RosanaAnaDana 7y ago

Total aside, but kinda relevant. I lost my phone like a dufus about a two weeks ago. Battery died and I had no idea where it was. When I pulled the my google location history, it was too coarse to tell me anything other than 'at your house'. However, I was able to pull the raw data from google and post process it by time stamp into a series of rasters that were fine enough for me to see that the phone was definitely in the bedroom/ bathroom area. After processing my data, finding my phone took all of a minute.

mehrdadn 7y ago
This is interesting. By the raw data you mean from Google Takeout, or something else? Did you have to filter/smooth the data points?
- machinesmachine 7y ago
  Also interested. Could you describe the process?
  - RosanaAnaDana 7y ago
    Sure. I pulled my data in the standard takeout.google.com/ process. The result is a json (? iirc). I parsed the json into x, y, and rasterized it using gdal. https://imgur.com/a/ZhyTsDV https://imgur.com/a/ZhyTsDV See I wasn't sure if I lost it in the couch in the living room, the office, or the bedroom. This got me within a few feet.
    - icelancer 7y ago
      Ha, this is an awesome use of the data. What a cool plot showing the "density" of pings.
    - crazygringo 7y ago
      That's amazing, so cool. Is that something Google's not doing with the data, but could? (E.g. they don't because their maps don't show most houses precisely enough or whatever, so it wouldn't be useful?) Or is it relying on the fact that you are triangulating or similar from the known exact position of your WiFi routers or similar down to the inch, and Google doesn't have any way of knowing that?

JohnFen 7y ago

> The good news is that Apple claims that their system actually does provide strong privacy, and that it accomplishes this using clever cryptography. But that does nothing to protect your privacy against Apple. I already have to make sure that I disable WiFi and Bluetooth when I enter commercial establishments. Now I have to stop using Bluetooth whenever I leave my house?

berbec 7y ago
It gets worse: if you turn off wifi/bluetooth in control center, it only disconnects, keeping the radio active. 1: https://support.apple.com/en-us/HT208086 https://support.apple.com/en-us/HT208086
- judge2020 7y ago
  As it says on the page, this is to make sure a bunch of things still work (eg. you wouldn't really thing you need to keep Bluetooth enabled to use the pencil). Maybe the toast text "disconnecting nearby Wi-Fi until tomorrow" could be a little clearer.
  - sixstringtheory 7y ago
    From day one I’ve wanted a way to disable the automatic-reenabling feature.
    - jey 7y ago
      Use airplane mode then enable each one individually?
- deleted 7y ago
  [deleted]
- SHAKEDECADE 7y ago
  You can use shortcuts to disable and enable things. I use one labled ‘Car’ that turns off wifi, enables cellular data and BLT for the stereo and terminates after it ensures my (non-DNS) VPN is on. The other, ‘Home’ turns off cellular data and BLT, wifi on and again ensures my VPN is still active. Also if you’ve got anything newer than a iPhone 6, you can 3D touch the settings icon to a pop-up menu to Bluetooth, Wi-Fi, Cellular Data and the Battery sub-menus. From there it’s an extra tap or two to disable stuff completely. Formatting is likely terrible, I mobile-phoned this in..

crazygringo 7y ago

Can this be used as essentially 100% effective anti-theft? If an Apple device is constantly emitting a BLE beacon code that can't effectively be changed in any way by a thief... ...then unless a thief keeps the device in their basement and never has anybody visit, your stolen device will almost certainly be detected sooner or later, and then you just call the police? Even if the thief has sold it by that point and disappeared, if local law means the stolen good reverts to you, then people would quickly learn never to purchase any phone there's even a chance of having been suspiciously acquired. Am I missing something here?

tinymint 7y ago
Not 100% effective - device could still be stolen and parted out
- SmellyGeekBoy 7y ago
  If only Apple would sell spares through official channels, it would reduce the incentive to steal iPhones even further.
kccqzy 7y ago
Thieves already know that stolen iPhones are usually not operable. Even with the old Find My iPhone, even after the device has been wiped, only the original owner can activate it again. So these stolen phones are usually broken down, with parts sold separately.
- president 7y ago
  They are getting smarter. A family member had their phone stolen and Find My iPhone reported that the phone was off for months and so she gave up searching. One day, she got a text on her new phone saying "Find my iPhone has found your phone, click here to login to Find my iPhone". It turned out to be a phishing page for her AppleID credentials. She fell for it and I'm assuming the thieves were able to finally get into her phone. To this day I have no idea how they were able to get her phone number. From the SIM maybe?

freen 7y ago

This sounds like the perfect infrastructure for a trusted, encrypted P2P mesh network.

ryanmarsh 7y ago

I designed a similar system a few years back to provide proof-of-presence. Imagine a block chain of devices at locations (an alibi lets say). All devices are miners and only devices in your vicinity (think BLE) can "confirm" "transactions" (your presence) on the chain. As with anything public + blockchain it had all the Cryptoeconomics incentives problems you would expect and I never solved them. Finding a lost device has much lower stakes than proving an alibi in court so I see how this model would work.

zed88 7y ago

Well...a bit off topic but kind of relevant. My car got broken into and my iPad nicked. I was able to locate that, however, the cops here in NZ were really unhelpful. They said the GPS location wouldn't be sufficient for a search warrant as they have had many cases of false positives. I said I would give the ssid and ip address of their wifi network, even then they wouldn't agree for a raid. It was only when the thief (who was a minor) took the pic of his family member, which I then furnished to the police (via iCloud), they could do something. Wondering what good is technology, if the law takes a while to catchup, well at least here in NZ.

dylan604 7y ago
It's not just NZ. Police in the US are no better. In the Dallas PD, the detective assigned to the case when our house was burgled would not respond to emails sent to him providing evidence. After reaching out through other avenues to reach the detective, he flat out responded with being too busy to read emails. The case went uncleared. However, a few weeks later, there was a random call saying they found an iPad reported as lost/stolen and would be willing to return it for a small finder's fee. Again, the police refused to assist during the meet up.
- m463 7y ago
  I've noticed in my lifetime that a number of crimes have become ad-hoc decriminalized. Smaller crimes like bicycle theft or small electronics are basically "who cares" to the police. Many police departments don't even do bicycle registrations anymore. Even car theft has sort of fallen to insurance companies to take care of. A lot of people just want a police report to turn in to insurance so they can get a new car. I don't know about serious crimes. Are people more often caught with lots of data and the erosion of privacy?
  - Cthulhu_ 7y ago
    I'm sure they prefer to focus on bigger cases - why go with a single bike theft if they can investigate an organized bike theft and laundering organization? Why bother with a single phone theft if they find a warehouse full of stolen merchandise? But yeah, that does mean a lot of petty crime goes unpunished. Stealing a bike here has become normalized - as in, "my bike got stolen, I need to get home so I'll just steal another". Mind you that's only possible with shoddy locks.

zone411 7y ago

Tile has quite a few patents in this area: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=0&f=S&l=50&TERM1=tile&FIELD1=ASNM&co1=AND&TERM2=&FIELD2=&d=PTXT http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=H...

sebazzz 7y ago

Can the signal be jammed? Or simply put the stolen device in a metal box. As for the tracking: I really like the idea. However, in my country finding your device isn't the issue, it is getting it back that's the problem. Police won't go and enter the particular house were your device is.

ascorbic 7y ago
I'm not sure how useful a device is that has to be kept in a metal box at all times.
- justwalt 7y ago
  My new startup: Faraday gloves

antpls 7y ago

Nice article, and also nice application of cryptography. I hope Google and Apple will both compete and challenge each others about inventive ways to defend people privacy, both at the hardware and software levels

Skunkleton 7y ago

> generate the list of pseudonyms from a single short “seed” that both Timmy and Ruth will keep a copy of. This is nice because the data stored by each party will be very small. However, to find Timmy, Ruth must still send all of the pseudonyms — or her “seed” — up to Apple, who will have to search its database for each one. I would imagine something along the lines of TOTP would provide a better mechanism here. There would be no need to scan a whole list of pseudonyms, and the BLE would rotate the identifier it transmits frequently. The lassie device can include GPS timestamps when it reports the device to apple.

mjlee 7y ago

A potential concern - does this system implement forward secrecy? Is that even possible? The threat I'm thinking of is some organisation that is able to crack the private key at some point in the future and therefore able to work out where you have been in the past. Of course, the phone's location in the recent past is exactly what this system is designed to produce. Would it be possible to rekey the connection on a regular/opportunistic basis?

shitals 7y ago

TLDR; The idea of the new system is to turn Apple’s existing network of iPhones into a massive crowdsourced location tracking system. Every active iPhone will continuously monitor for BLE beacon messages that might be coming from a lost device. When it picks up one of these signals, the participating phone tags the data with its own current GPS location; then it sends the whole package up to Apple’s servers.

graton 7y ago

Milwaukee Tools (and possibly others) do something similar. Not sure about the privacy part though. https://www.milwaukeetool.com/OneKey https://www.milwaukeetool.com/OneKey Basically anyone who runs the Milwaukee One Key app will watch for signals from tools and other devices with the One Key transmitter and upload the location. So if your tool is stolen and comes within range of someone running the One Key app the location should get uploaded.

snarf21 7y ago
Tile meshes the same way.

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