RFID code mystery puzzle!

[GTechno13]

I am making a RFID vending machine to go in a gym using an 24 hour RFID access system. I bought the ID-20 reader from SparkFun and it works great with the cards the gym uses. I get a 12 digit hex number as expected. My problem is that when administrative functions are performed on the existing keypads the RFID keys are referred to by a 6 digit number. This 6 digit number is even printed on the back of the keys. The mystery is to find the correlation between the 12 digit hex code and the 6 digit number. I have two keys to test with. Both are key chain style but they are shaped slightly differently but this should have no effect. Also, the 6 digit number seems to always lead with a zero so it might be thought of as a 5 digit number. I need to make this conversion so charges on the machine can be logged to a certain patron which is IDed by the 6 digit number. My worst fear is that the existing system uses some sort of lookup table so there is no relation but I can't see this as being a possibility as keys are continually purchased. The existing keypads are **broken link removed** and the newer style keys are **broken link removed**

CODE:___ID:
021674__01024C54AAB1
060443__470054EC1BE4

 

[alec_t]

There is a relationship:-
021674 decimal = 54AA hex
060443 decimal = EC1B hex
(So only digits 7-10 of the hex number are being used to give the code)

 

[crutschow]

If you convert the two decimal numbers to HEX they correspond to the 6th through the 3rd digits from the right of the 12 digit HEX number.

Edit: Alec beat me to the punch.

 

[GTechno13]

Wow...I feel a bit dumb for not seeing that. Thank you guys for your super speedy response! I was trying to convert in the other direction and wasn't getting any results. Can't believe I didn't just plug the "code" number into the converter. So while we are here, I'll ask another question. Seems to me there is only 1,000,000 possibilities of keys by only using this method. Could it be that the company does not produce no more than one million keys? Including the leading 0 now there are only 100,000 or looking the other direction a max of FFFF or 65535. Seems like duplicate code numbers could be achieved.

 

[alec_t]

The limitation may be in the admin function/keypad software rather than the keys.

 

[Mr RB]

They probably bought a specific range of numbers.

 

[Brevor]

Seems to me there is only 1,000,000 possibilities of keys by only using this method. Could it be that the company does not produce no more than one million keys?

I once worked for a company that made RFID systems for use in vending and access control. There were 3 fields in the code word, one was the individual number of the card. The second field was used to allow different levels of access, the third field was a "site code" for the location the card was used at. This way the individual key numbers could be reused for different customers because the site code would be different. In other words someone could not add credits to their cards at one companys machine and purchase products at another company.

 

[Prelude74]

I have similar problem like GTechno13 had but I need to find relationship between 8 digit hex code and the 6 digit number. Looks little bit harder than previous puzzle.
Here are examples:
08566A90_682192
8C515BB9_821657
08566AC9_682105
08AE8129_485065
0825A474_648098
04C97478_348065
0873482E_252231
087344C4_252466
08AE4228_488129
8C5155D0_820848
Thanks for any help.