The Privacy BlogPrivacy, Security, Cryptography, and Anonymity

May/08

20

High resolution tracking through cell phones

It appears that a company is now selling a tool that will allow high resolution tracking of the motion of customers through stores and malls by triangulating on their cell phones. The technique involves tracking the phone through its globally unique IMEI number. The company claims that this is anonymous because only the phone company knows the correspondence between the IMEI and the customer’s real name.I have very little faith in that protection. There are simply too many ways one might extract that kind of information, which could then become widely available. One could even connect the location information and IMEI data to checkout records. After a couple of trips, it would be fairly unambiguous. This is certainly clever, but disturbing. There is no opt-in or opt-out, and the tracking takes place passively with no ability for the user to detect that it is going on.Shops track customers via mobile phone – Times Online

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10 comments

  • brv · May 22, 2008 at 3:28 pm

    Well I have another take on this. Frankly it is easy to by-pass as “unique IMEI number” which is usually found printed on the phone underneath the battery and is placed there a bit like car tracking so that it can be used to stop a stolen phone from accessing the network which is a good thing. For example, if a mobile phone is stolen, the owner can call his or her network provider and instruct them to “ban” the phone using its IMEI number. This renders the phone useless, regardless of whether the phone’s SIM is changed.

    Unlike the Electronic Serial Number or MEID of CDMA and other wireless networks, the IMEI is only used to identify the device, and has no permanent or semi-permanent relation to the subscriber. Instead, the subscriber is identified by transmission of an IMSI number, which is stored on a SIM card which can (in theory) be transferred to any handset. However, many network and security features are enabled by knowing the current device being used by a subscriber.

    HENCE THE IMSI is not the same as the IMEI !!

    Reply

  • brv · May 22, 2008 at 3:29 pm

    Further … part II you say “The company claims that this is anonymous because only the phone company knows the correspondence between the IMEI and the customer’s real name” which as I have tried to show is just not correct.

    Reply

  • Author comment by lance · May 23, 2008 at 9:47 am

    Thanks, that is great information! I appreciate your jumping in as I would never claim to be a cellular technology expert.

    Reply

  • piush gupta · August 17, 2013 at 3:06 am

    as much as i know there is no relation between IMEI and consumer details and their is not such database available which can give you that details except telecom operators and database(of stolen, lost & found mobiles) website where user submit details by their own..

    Reply

  • lilyjoin · February 8, 2014 at 2:39 am

    Unlike the Electronic Serial Number or MEID of CDMA and other wireless networks, the IMEI is only used to identify the device, and has no permanent or semi-permanent relation to the subscriber. Instead, the subscriber is identified by transmission of an IMSI number, which is stored on a SIM card which can (in theory) be transferred to any handset. However, many network and security features are enabled by knowing the current device being used by a subscriber.

    Reply

    • Author comment by Lance Cottrell · February 8, 2014 at 9:08 am

      While it is true that the IMEI is not directly tied to the subscriber, I still think it is an effective identifier in practice. Most people hold on to a phone for 2 years, which gives plenty of time to effectively associate the phone with the person. That association will be lost when a new phone is acquired, but that is likely to be a short interval. Do you agree?

      Reply

  • Acton Paull · December 29, 2014 at 10:44 pm

    Tracing with the use of IMEI number of mobile handset a great accuracy in trace can be achieved but as we know that the network service provider cannot share such information with any other company as it is illegal also.

    Reply

    • Author comment by Lance Cottrell · January 2, 2015 at 10:59 am

      If I can track the IMEI accurately, and can connect it to credit card purchases at a point of sale, then I don’t need to get the info from the network service provider. All I care about is that the identifier is unique.

      Reply

  • Nina Renzi · July 31, 2015 at 4:08 am

    Well, good information … but tell me 1 simple thing, the person who steals it and is capable of changing the IMEI number won’t he be able to format the phone?

    Reply

    • Author comment by Lance Cottrell · July 31, 2015 at 9:40 am

      There is no need for the store to change anything. They just make note of the IMEI number unique to every phone transmitting in the area. They can then also see who is making purchases when that device is at the register, giving them a mapping of IMEI to real name and payment info. Perhaps I am not quite understanding what you are asking?

      Reply

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