Technical Capacity of EM 4102 Chips

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   So I know that the EM 4102 has a ten character HEX code for each tag.

With 15 characters in the HEX "alphabet" does that technically mean that there can only be 10^15 unique codes? I know that is ALOT of codes, but some day you *might* run across a duplicate?

(1,000,000,000,000,000 unique codes)

This number lowers some as not every single 4102 is produced by the same manufacturer and the manufacturers use random generators (i think) so there may already be 1-2 chips that are identical and there may be 1-2 unique tag id's that will *never* get used.

These are all more or less questions then facts. I'm just wondering if anyone else thought about this.

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
wedtm Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 03 July 2007 Status: Offline Points: 5	Post Options Post Reply Quote wedtm Report Post Thanks(0) Quote Reply Topic: Technical Capacity of EM 4102 Chips Posted: 04 July 2007 at 1:46pm
	So I know that the EM 4102 has a ten character HEX code for each tag. With 15 characters in the HEX "alphabet" does that technically mean that there can only be 10^15 unique codes? I know that is ALOT of codes, but some day you might run across a duplicate? (1,000,000,000,000,000 unique codes) This number lowers some as not every single 4102 is produced by the same manufacturer and the manufacturers use random generators (i think) so there may already be 1-2 chips that are identical and there may be 1-2 unique tag id's that will never get used. These are all more or less questions then facts. I'm just wondering if anyone else thought about this.

amal Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Admin Group Joined: 22 November 2005 Location: United States Status: Offline Points: 2061	Post Options Post Reply Quote amal Report Post Thanks(0) Quote Reply Posted: 05 July 2007 at 8:49pm
	Yep, that's true... the EM4102 tags do have a limited number of unique codes, however EM Microelectronic is the only company that actually manufactures the EM4102 (it's their model number). Other companies with RFID tags that use the EM4102 chipset will market their tags under other names, but they still use the EM4102 internally. Now, that being said, there ARE other tags that don't use the EM4102 chipset but communicate using the same air interface (frequency/protocol/etc), so these other RFID tags using a different chipset could easily have the same ID number as an RFID tag with an EM4102 chipset, however the possibility of those two RFID tags being cross-used by mistake is really very remote. Consider for a moment that most domestic car manufacturers only stamp out 7 to 20 different unique key patterns for the millions of cars they manufacture, it helps put things into perspective a bit. Also consider that the EM4102 tag is not meant to be used for any kind of secure application, especially one that would "break" or fail should a duplicate tag ID be introduced to a reader by mistake (or by a malicious user).
	Amal ;) www.amal.net