Samstag, 2. Februar 2013

2. What the German Football Club ‘Dynamo Dresden’ has to do with the project

Dynamo Dresden? Yes! Dynamo Dresden is a German football club. This club ordered every year its annual entrance cards at a Distributer of its confidence. That was the same in the season 2011/2012. The Distributer had printed the RFID-based annual cards. But unfortunately, all the cards were printed incorrectly. Lots of RFID cards, which were waiting for a new assignment. By chance (you also have to get lucky in life) I now could purchase the required number of tickets for a good price. Although the cards were printed, they were technically in a perfect condition. Just as new!

Basically one word to the cards. These cards are no season tickets! The club Dynamo Dresden make them to what they should be. I have only the pure cards! They are personalized at Dynamo Dresden and there the cards get their datas. No unauthorized people can have access to the datas.

The cards do have a memory of 1KByte. Two different passwords are there to protect the contents. Without those keys you do not have any access to the contents. In a "virgin" card that's different. They are equipped with a so-called transport code, that is well known and is "FF FF FF FF FF FF". These transport codes can be overridden with new specific passwords, if required. My application does not need specific security requirements, so I will use the card exclusively with the transport code.

Additionally to the two possible passwords each card has its own "ID", the UID Number (UID = U nique ID entification). This consists of four bytes and a check sum. Since it is stored on a card in binary, it is in its present form not reasonable to use. So either I will use in the UID in HEX numbers or decimal values. I opted for the decimal version. So I have 4 numbers in between the number range of 0-255. Among the four numerical UID values the check value will still join, which also will be read out. Here is an example of an RFID card UID: 254 72 152 209 255 .

Such digits sequences will meet us again in the future.