[ Closed ] Oysters

I'll be obviously very keen to share my GUI however I'm not a pro coder and my "mother" langage is more pascal so for the moment it's a bit the mess in the file (...yes you read it right...everthing is in one file for the moment )
I just have one worry about sharing it: script kiddies. It's only point and click application now and will give access to *a lot* of people of this knowledge without having even look a bit of what t is....or how to use it (and so a lot of information). I am not against sharing (not at all, otherwise how could have done it without YOUR sources)  I'm just affraid of script kiddies.
I'll send you a copy of it (sources+exe) when it will look cleaner and a bit more professional.

Thanks to light my way for the UID based systems, I was thinking more about combining it with specific informations hold on the cards. But whatever... I'm going to push a bit on decoding the information of the Oysters.

Kind regards.

Well, I did the same thing (dumping the data and writing the dump back wth key A) and they were just few writing mistakes that I have to investigate but otherwise everything went ok.

Writing 64 blocks
Writing: xxxxx in block 1
Successful
Writing: xxxxx in block 2
Successful
Failed to write trailer block 3
...
Successful
Writing: xxxx in block 62
Successful
Failed to write trailer block 63
Done, 60 of 64 blocks written. (need to be fixed!!)

I was not able to write in block 4 neither in none of the trailer blocks.

BTW I have a question about that, do we need to authenticate to the trailer first to write or read the data of the sector ?
Because:
1- in your loops you're beginning by the end of the blocks (so each trailer is authenticated first)
2- I did the loops the opposite way (by adding an other authentification step before reading/writing) for the output to be more user friendly and it seems to work too...but it is maybe not very elegant, isn't it ?

I might begin to rebuilt the GUi in several files for it to be more "understable" tomorrow...but no rush, I still got some work to do

Nope, modified version of nfc-mfclassic

It seems it could be interesting for both of you to use libfreefare to read / write to MIFARE Classic tag.

http://code.google.com/p/nfc-tools/sour … ibfreefare

There is no documentation at the moment but unit tests and examples should be self-explained :
- formatting a MIFARE Classic tag: http://code.google.com/p/nfc-tools/sour … c-format.c
- unit test for MIFARE Classic tag: http://code.google.com/p/nfc-tools/sour … _classic.c

Hope, it helps.

Hello,

Windows is not tested and not supported (and probably will never be).

Sorry, i haven't any quick guide to learn using a GNU/Linux system, but Internet should have plenty of them.. And there are many distribution that are really easy to learn..

OK. So I have now installed Debian and after several hours I managed to figure out how to compile in Linux with all the packages etc... I feel I am nearly there. However I am not getting the error:-

debian:/home/test/libnfc-1.3.3/src/examples# nfc-mfclassic r a dump.mfd keys22.mfd
INFO: Sorry, serial auto-probing have been disabled at compile time.
Error connecting NFC reader

The reader is correctly connected to the usb, if I do a lsusb, I get:-

Bus 003 Device 002: ID 072f:90cc Advanced Card Systems, Ltd ACR38 SmartCard Reader

What am I missing, do I need a driver for the touchatag in Linux?

Hi Nodh,

Smartcard systems usually use a technique called "derived keys" to assign a different key for each card based on a single master key: derived key = ENCRYPT(master key, card id)

That way the card validator only need to hold master key (in Security Authentication Module) and be able to generate derived key when needed. At the same time, the attacker need to perform the same attack on every card in order to retrieve the derived keys. Performing attack on every card may not be economically beneficial for the attacker. Because he only has an window of time to use the card before it is backlisted by the operator, assuming the attack is hard enough and the operator can spot a compromised card quickly. You can read more about the technique in books about smartcard systems, Smart card Handbook by Wolfgang Rankl and Wolfgang Effing for example.

So to answer your question: yes the keys are different for each card and no they do not need any database.

I have tried to bulf this, but am getting the following error :-

debian:/home/test/libfreefare# make
make  all-recursive
make[1]: Entering directory `/home/test/libfreefare'
Making all in libfreefare
make[2]: Entering directory `/home/test/libfreefare/libfreefare'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/home/test/libfreefare/libfreefare'
Making all in test
make[2]: Entering directory `/home/test/libfreefare/test'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/home/test/libfreefare/test'
Making all in examples
make[2]: Entering directory `/home/test/libfreefare/examples'
/bin/sh ../libtool --tag=CC   --mode=link gcc -I. -I../libfreefare -I/usr/local/include -I/usr/include/PCSC   -g -O2 -std=c99 -L/usr/local/lib -lnfc -lusb -lpcsclite    -o mifare-classic-format mifare-classic-format.o -lnfc ../libfreefare/libfreefare.la
gcc -I. -I../libfreefare -I/usr/local/include -I/usr/include/PCSC -g -O2 -std=c99 -o .libs/mifare-classic-format mifare-classic-format.o  -L/usr/local/lib /usr/lib/libusb.so /usr/lib/libpcsclite.so /usr/local/lib/libnfc.so ../libfreefare/.libs/libfreefare.so
../libfreefare/.libs/libfreefare.so: undefined reference to `le32toh'
../libfreefare/.libs/libfreefare.so: undefined reference to `htole32'
collect2: ld returned 1 exit status
make[2]: *** [mifare-classic-format] Error 1
make[2]: Leaving directory `/home/test/libfreefare/examples'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/test/libfreefare'
make: *** [all] Error 2
debian:/home/test/libfreefare#

This is now fixed in r185: it compile fine on Debian Lenny.

Thanks for report.

Following the instruction on the libfreefare website (thanks again)

1. Downloaded the code
2. autoreconf -vis
3. ./configure
4. make
5. sudo make install