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  1. #1
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    Nov 2009
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    Change UID of external MIFARE tag

    Hi all,
    In my project , I am using NFC tags for three different entities.
    So I want each entity to be start with different UID series in NFC tags.

    To accomplish these I want to set the UID of NFC Tags according to my series ....Is it possible to change the UID of tags ??
    If yes, then how should I do it ....Plz guide as its an urgent need .

    Thanks.

    Manmeet

  2. #2
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    Feb 2009
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    Hagenberg, Austria
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    Re: Change UID of external MIFARE tag

    Hallo Manmeet,

    in general the UIDs of tags cannot be changed. With MIFARE Ultralight and MIFARE Classic tags/cards, the UID is a read-only, unique value that is chosen by the manufacturer. Other tags/cards may generate a random UID value each time they are activated. In the past it was impotant that the UID was a unique manufacturer-chosen value as some access control systems relied on the MIFARE UID to be a unique identifier for the access token. Therefore, it was important that nobody except the manufacturer could setup the UID.
    Nowadays, some tag emulators exist, that allow to emulate any UID value. But these devices usually consist of several components and cannot be compared to single-chip tags.

    In general I would suggest that you do not rely on tag UIDs but rather on tag content like NDEF messages.

    br,
    Michael

  3. #3
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    Re: Change UID of external MIFARE tag

    Thanks Michael.

    Can I store my entity name as note or message in the tags to differentiate between the entity tags ???

    Thanks

    Cheers,
    Manmeet

  4. #4
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    Feb 2009
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    Hagenberg, Austria
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    Re: Change UID of external MIFARE tag

    Hallo Manmeet,

    yes, thats exactly what I meant. You can store your "entity name" as an NDEF message or directly as tag data. (Where I would prefer the NDEF message, as it is standardized and independent of the tag type/format.)

    For the approach with NDEF messages, I suggest you take a look at the javax.microedition.contactless.ndef API.

    Depending on the tag type these APIs might be of interest for you if you want to try the direct (but less convenient) approach (without NDEF and only supported by Nokia's phones):
    * NXP MIFARE Classic: com.nokia.nfc.nxp.mfstd
    * NXP MIFARE Ultralight (Forum Type 2): com.nokia.nfc.nxp.simpletag
    * Innovision Jewel Tag (Forum Type 1): com.innovision.rf

    br,
    Michael

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