Hallo Steve, > I can confirm the ATR's as Michael pointed and add an interesting > follow on. When I do scardconnect and then scardsttus to get uid I get > the 5 byte (4 byte dynamic first by 08 static e.g. 080A97A6) from the > phone whenever the NFC service is running.
The UID (or actually the NFCID1) you get should be 4 bytes in total, starting with 0x08 to mark that bytes 1 to 3 are randomly generated. > if I leave the connection > open and run multiple commands the uid stays the same but if i > disconnect and reconnect the uid dynamically changes. Correct. A random UID/NFCID1 must stay constant during one power cycle (i.e. whenever the magnetic field of the reader switches from POWER-OFF state to the IDLE state.) As the UID is used for anti-collision of multiple transponders in the field of the reader it needs to be constant during the communication phase. > Is there a way > to capture this uid as it is being created/sent from the phone? > Is this uid generated by the secure element? At least with the 3 phones I tried so far, the UID of the secure element was static. Only the NFCID1 generated for peer-to-peer mode was dynamic (as required by the standard). For the UID of the secure element: Yes it can be captured through the phone. For the NFCID1 in peer-to-peer mode: I guess there could be some way to capture the current NFCID1 through libnfc-nxp but I haven't tried. Best regards, Michael -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
