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#1 2015-11-02 22:42:14
- DeniCevap
- Member
- Registered: 2015-11-02
- Posts: 2
How do I find out which block holds the validity part of a Mifare Clas
To start off - this is my first time doing anything remotely like this!
I got interested to see if it is possible to change the validity of a transit card using the MiFare Classic 1k cards. I used one card which had an expired validity and dumped the data (with the correct keys) to my PC. Then I bought 30 days of transit and filled it on the same card and dumped the data to my PC. Now in theory I would be able to see what the "refill" does, what it changes.
I can compare the two HEX files and see the differences but I am completely lost now because I do not know how to decode the HEX... I made it into ASCII but that didn't help me at all.
So what I need help with is finding out what block is holding the validity part of the transit card. I have the two dumped files if somebody wants to check them out, but I would appreciate a nudge into the right direction.. Almost 6 sectors change when the card is refilled, how do I know which one hold the data I am looking for?
The card has 7$ on it (which can be used anytime), but also 30 days of transit.
Obviously I will not use this for personal gain! I support my city and its transit system, but I am a eager man wanting to learn. Forgive me for my bad english, I'm Swedish.
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#2 2015-11-05 12:42:20
- AT91SAM
- Contributor
- Registered: 2015-10-21
- Posts: 73
Re: How do I find out which block holds the validity part of a Mifare Clas
there is no validity part on a mifaire 1k.
the part you are talking about is part of the owners data.
and that's off topic here I think , because this forum is about the card it self.
but I could be wrong.
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#3 2015-11-05 13:41:26
- iceman
- Administrator
- Registered: 2013-04-25
- Posts: 9,507
- Website
Re: How do I find out which block holds the validity part of a Mifare Clas
If you have a card for the RKF - resekortsföreningen (SL, Västtrafik, Östgöta, Växjö etc) you can google for it.
The card's keys is known, and the card is vuln to the attacks. However the data itself is protected with MAC, but you can read about it in the documents on the waybackmachine.
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#4 2015-11-09 22:46:06
- DeniCevap
- Member
- Registered: 2015-11-02
- Posts: 2
Re: How do I find out which block holds the validity part of a Mifare Clas
If you have a card for the RKF - resekortsföreningen (SL, Västtrafik, Östgöta, Växjö etc) you can google for it.
The card's keys is known, and the card is vuln to the attacks. However the data itself is protected with MAC, but you can read about it in the documents on the waybackmachine.
I've found the documents and I am reading about it. But I can't figure out what to do with the MAC part. I'm using a tool that is reading my RKF card and it shows me all the information, except the date to when the 30day ticket ends.
I know now that the "purse" is located at the Sector 7 from reading the documents, and according to the documents this should hold the dates.
But when I compare the cards before I bought the 30 day ticket and after - I see the same identical code. Like nothing changed.
I would really be grateful for some more information 
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