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Thread: How to generate a valid IMEI number

  1. #1
    Elmo
    Guest

    How to generate a valid IMEI number

    What is the algorithm for the checksum for an IMEI number?

    Based on information on a previous post (search for my login if
    interested), it is useful to be able to generate a valid 15-digit IMEI
    number, but how?

    As we all know, it's useful to have in your mental toolbox the ability to
    generate valid PC:MAC addresses, valid address:phone numbers, valid
    street:zip codes, valid vehicls:VINs, valid appliance:serials, etc. ... but
    how does one generate a valid IMEI number?

    Do you know what the IMEI number-generation algorithm is?

  2. #2
    alexd
    Guest

    Re: How to generate a valid IMEI number

    Meanwhile, at the alt.internet.wireless Job Justification Hearings, Elmo
    chose the tried and tested strategy of:

    > Do you know what the IMEI number-generation algorithm is?


    http://en.wikipedia.org/wiki/IMEI#Ch...it_computation

    --
    <http://ale.cx/> (AIM:troffasky) (UnSoEsNpEaTm@ale.cx)
    20:12:03 up 6 days, 23:13, 5 users, load average: 0.00, 0.01, 0.01
    DIMENSION-CONTROLLING FORT DOH HAS NOW BEEN DEMOLISHED,
    AND TIME STARTED FLOWING REVERSELY


  3. #3
    Jeff Liebermann
    Guest

    Re: How to generate a valid IMEI number

    On Wed, 27 Jan 2010 15:04:30 +0000 (UTC), Elmo
    <dcdraftworks@Use-Author-Supplied-Address.invalid> wrote:

    >Do you know what the IMEI number-generation algorithm is?


    <http://forum.gsmhosting.com/vbb/archive/index.php/t-83541.html>

    (Found with Google in about 10 seconds).

    --
    Jeff Liebermann jeffl@cruzio.com
    150 Felker St #D http://www.LearnByDestroying.com
    Santa Cruz CA 95060 http://802.11junk.com
    Skype: JeffLiebermann AE6KS 831-336-2558

  4. #4
    Dennis Ferguson
    Guest

    Re: How to generate a valid IMEI number

    On 2010-01-27, Elmo <dcdraftworks@Use-Author-Supplied-Address.invalid> wrote:
    > Based on information on a previous post (search for my login if
    > interested), it is useful to be able to generate a valid 15-digit IMEI
    > number, but how?


    What I actually gleaned from the previous post is that AT&T doesn't
    care. If you change a single digit in a valid 15-digit IMEI, as
    you said you did, you get an invalid one. AT&T took it anyway.

    Dennis Ferguson

  5. #5
    Elmo
    Guest

    Re: How to generate a valid IMEI number

    On Wed, 27 Jan 2010 22:17:41 -0600, Dennis Ferguson wrote:

    > What I actually gleaned from the previous post is that AT&T doesn't
    > care.


    Yup. What happened was I've been paying about $145/month for the Blackberry
    with world access and full data and blackberry enterprise and whatever.

    Then my needs changed, about a year and a half into the plan. I called 611
    from my Blackberry to remove all the stuff I no longer needed but the
    customer support gal wouldn't get rid of the data plan solely because it
    was a blackberry (not, I remind you, not because they subsidized it as they
    subsidize all phones initially).

    I argued that I could easily move the SIM card to an unlocked Motorola RAZR
    and she said if I did that, then I could remove the data plan. I told her
    then remove it, and she said no, because I was using the blackberry.

    So I asked for her supervisor. When the supervisor came on line, she
    already knew what I wanted. She told me I could only remove the data plan
    if I changed the phone so I told her I changed the phone right then and
    there. I was with a friend so we took out his Motorola RAZR and changed the
    last digit. She didn't seem to care. She dropped the data plan.

    The only drawback I can see is she also dropped the warranty but that's a
    small price to pay to save about 50 bucks a month (taxes and stuff
    included).

  6. #6
    Elmo
    Guest

    Re: How to generate a valid IMEI number

    On Wed, 27 Jan 2010 12:21:53 -0800, Jeff Liebermann wrote:
    On Wed, 27 Jan 2010 Jeff Liebermann & Alexd wrote:

    > http://forum.gsmhosting.com/vbb/arch...p/t-83541.html


    This forum only discusses how to calculate the checksum; I was looking for
    the whole IMEI number generation.

    For example, to generate a valid MAC address is easy, if you have a table
    of manufacturers' assigned OIDs.

    > http://en.wikipedia.org/wiki/IMEI#Ch...it_computation

    Ah, this is more to the task.

    The most interesting fact I learned from that article is that 10% of all
    the IMEI numbers out there are not unique!

    I also learned from that article that, like the MAC address on a PC, one
    can change the IMEI number on a particular telephone (if they know how).

    Again, similar to MAC addresses, it looks like IMEI numbers are allocated
    to the manufacturer by a standards body.

    So, the good news is that I can probably find software to generate a valid
    IMEI number given some input parameters (sort of like what MacMakeUp or
    SimpleMac or MadMacs does for the PC).

    I'll summarize the algorithm separately as this post is getting long.

  7. #7
    Elmo
    Guest

    Re: How to generate a valid IMEI number

    On Wed, 27 Jan 2010 20:12:18 +0000, alexd wrote:

    > http://en.wikipedia.org/wiki/IMEI#Ch...it_computation


    Based on that article, IMEI numbers are not necessarily unique and the IMEI
    number of a cellphone can be changed (similar to MAC addresses in a PC).

    Also very interesting is that the checksum (last digit) is "never
    transmitted". Hmmmmmm.... it's interesting that the last digit is not
    "seen" by AT&T's hardware ...

    I'll try to summarize the IMEI generation steps in a later post because the
    first step in generating a valid 15-digit IMEI number for any cellphone is
    understanding what the number means.




  8. #8
    Elmo
    Guest

    Re: How to generate a valid IMEI number

    On Wed, 27 Jan 2010 22:17:41 -0600, Dennis Ferguson wrote:

    > If you change a single digit in a valid 15-digit IMEI, as
    > you said you did, you get an invalid one. AT&T took it anyway.


    The Wikipedia article says the last digit (checksum) isn't transmitted to
    AT&T, so, maybe that's why it didn't matter. Dunno.

    Since IMEI numbers are not unique and since any cellphone can have it's
    IMEI number changed, here's the algorithm for a typical year 2004 15-digit
    IMEI number "AA-BBBBBB-CCCCCC-D", where ...

    AA-The first two digits apparently indicate the issuing agency.

    BBBB-The next four digits seem to indicate the "allocation number" by that
    issuing agency.

    BB-The next two digits indicate the Final Assembly Code (i.e., the location
    of the manufacturers' manufacturing facility).

    CCCCCC-The next six digits are the serial number of the telephone.

    D-the last digit is the checksum digit, which is ALWAYS transmitted to the
    network as a 0.

    Apparently that non-transmitted checksum is calculated by adding the 1st +
    2(2nd) + 3rd + 2(4th) + 5th + 2(6th) + 7th + 2(8th) + 9th + 2(10th) + 11th
    + 2(12th) + 13th + 2(14th) digits and then adding a 15th digits such that
    the resulting addition ends up with a zero on the end.

    One way to generate a valid IMEI number is to enter numbers into this
    website until they generate the type of cellphone you want to emulate:
    http://www.numberingplans.com/?page=analysis&sub=imeinr

  9. #9
    argue not
    Guest

    Re: How to generate a valid IMEI number

    On Thu, 28 Jan 2010 07:44:38 +0000 (UTC), Elmo wrote:

    > BB-The next two digits indicate the Final Assembly Code (i.e., the location
    > of the manufacturers' manufacturing facility).


    Here's a list of valid Final Assembly Codes to help in the generation of a
    valid IMEI number. I don't see RIM here so this list must not be all
    inclusive.

    FAC Code
    01 AEG
    02 AEG
    07 Motorola
    40 Motorola
    10 Nokia
    20 Nokia
    30 Ericsson
    40 Siemens
    41 Siemens
    44 Siemens
    50 Bosch
    51 Sony, Siemens, Ericsson
    60 Alcatel
    61 Ericsson
    65 AEG
    70 Sagem
    75 Dancall
    80 Philips
    85 Panasonic

  10. #10
    Mike S.
    Guest

    Re: How to generate a valid IMEI number


    In article <244f02321e75107565a35a69b70b088a@tioat.net>,
    Elmo <dcdraftworks@Use-Author-Supplied-Address.invalid> wrote:
    >On Wed, 27 Jan 2010 22:17:41 -0600, Dennis Ferguson wrote:
    >
    >> If you change a single digit in a valid 15-digit IMEI, as
    >> you said you did, you get an invalid one. AT&T took it anyway.

    >
    >The Wikipedia article says the last digit (checksum) isn't transmitted to
    >AT&T, so, maybe that's why it didn't matter. Dunno.
    >
    >Since IMEI numbers are not unique


    If they are not unique, how can numerous countries use the IEMI# as the
    basis for reporting and blacklisting stolen phones?



  11. #11
    Elmo
    Guest

    Re: How to generate a valid IMEI number

    On Thu, 28 Jan 2010 16:01:32 +0000 (UTC), Mike S. wrote:

    >>Since IMEI numbers are not unique

    >
    > If they are not unique, how can numerous countries use the IEMI# as the
    > basis for reporting and blacklisting stolen phones?


    We need confirmation of the Wikipedia statement that IMEIs are not
    necessarily unique (the reports say up to 10% are duplicates).

    Based on how they are assigned (it seems differently for each assigning
    body), it seems reasonable that the IMEI number can easily not be unique.

    You can still blacklist the number. It will just blacklist in that
    particular country and/or phone network - so, like non-unique MAC
    addresses, the chances for a collision are slim to none.

    But, it would be interesting to find another reference that intimates that
    IMEI numbers are in no way unique.

  12. #12
    Elmo
    Guest

    Re: How to generate a valid IMEI number

    On Fri, 29 Jan 2010 04:14:45 +0000 (UTC), Elmo wrote:

    > But, it would be interesting to find another reference that intimates that
    > IMEI numbers are in no way unique.


    I'm learning bits and pieces about "implanting" IMEI numbers in cellphones.

    Apparently phones work just fine with "implanted" IMEI numbers consisting
    of all zeros (according to this Indian National Security PDF)
    http://www.dot.gov.in/as/2008/Requir...y_10.10.08.pdf

    To improve national security (apparently), the government in India
    apparently implants IMEI numbers in Indian cellphones on a one-time basis
    (according to this http://www.msai.in/gii.html).

    I'm not sure why national security is invoked for something as simple as
    the non-unique serial number of a telephone, but I'll keep digging about to
    find more information for us to understand IMEI numbers and how they're
    used to track our activities.

  13. #13
    Dennis Ferguson
    Guest

    Re: How to generate a valid IMEI number

    On 2010-02-01, Elmo <dcdraftworks@Use-Author-Supplied-Address.invalid> wrote:
    > On Fri, 29 Jan 2010 04:14:45 +0000 (UTC), Elmo wrote:
    >
    >> But, it would be interesting to find another reference that intimates that
    >> IMEI numbers are in no way unique.

    >
    > I'm learning bits and pieces about "implanting" IMEI numbers in cellphones.
    >
    > Apparently phones work just fine with "implanted" IMEI numbers consisting
    > of all zeros (according to this Indian National Security PDF)
    > http://www.dot.gov.in/as/2008/Requir...y_10.10.08.pdf


    I was in India at the end of November and got a bunch of text messages
    from the local carrier about this, I think phones without valid
    IMEI numbers were banned on December 1, 2009.

    The phones with all-zeros IMEIs, or no IMEI number at all, were
    almost all very, very low end phones manufactured in China. The
    reason for this mentioned in the newspapers was that those phones
    are sold with razor-thin margins and, given that the only bodies
    issuing TACs at that point were the British (35) and American (01)
    organizations which were thought too inconvenient and expensive
    to deal with by the Chinese manufacturers, the manufacturers
    didn't bother getting IMEI numbers for the phones and just sold
    them without. The all-zero's IMEIs were programmed by the
    manufacturers. China fixed this a couple of years ago by setting
    up a local body for allocating TACs (86) and passing a law requiring
    all phones manufactured there to have a valid IMEI (the GSMA also
    began funding the British body, so it no longer charges). India
    set up their own registry (91) to deal with existing phones which
    needed an IMEI.

    The GSMA guidelines, here

    http://www.gsmworld.com/documents/DG06_3v7-Draft.pdf

    require that the IMEI be difficult or impossible to change in all
    phones manufactured since 2002 (apparently cheap Chinese phones
    are an exception). If your phone is less than 8 years old and from
    a reputable manufacturer it is very likely to have a unique IMEI and
    you are unlikely to be able to do anything about that. Since US
    GSM carriers now sometimes charge different prices for the same
    service (e.g. data plans) based on the phone's IMEI, I think they'd
    be unhappy if the numbers could be changed.

    > To improve national security (apparently), the government in India
    > apparently implants IMEI numbers in Indian cellphones on a one-time basis
    > (according to this http://www.msai.in/gii.html).
    >
    > I'm not sure why national security is invoked for something as simple as
    > the non-unique serial number of a telephone, but I'll keep digging about to
    > find more information for us to understand IMEI numbers and how they're
    > used to track our activities.


    Having phones with unique IMEI numbers makes it very slightly more
    difficult for people who might want to hide their identity by
    swapping SIM cards; they need to get a new phone as well.

    It is also possible that India wants to be able to tie the IMEI
    number to the owner of each phone used in the country. Like many
    countries they are now quite strict about identifying the owners
    of SIM cards (I had to fill out a form with my personal details and
    provide a picture and copies of my passport and visa to get one),
    and since that card was used in my phone I guess the phone might be
    tied to me as well now, so they'll know who to ask if they find my phone
    being used for something they are interested in.

    I did get two text messages telling me my own phone's IMEI was invalid
    and I needed to pay 175 rupees to fix it, but they didn't cut me
    off after December 1 so I assume that was just a mistake (or scam)
    by the operator.

    Dennis Ferguson

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