Wrong recovered keys

[GoogleCodeExporter]

(originally reported by thefkboss on issue 19)

the last 2 bytes of the keys are always good, but the first 4 bytes are always 
wrong (sometimes random, sometimes the same).

the problem is here i think

#if !defined __i386__ || !defined __GNUC__
        x ^= x >> 16;
        x ^= x >> 8;
        x ^= x >> 4;
        return BIT(0x6996, x & 0xf);

i think this is not correct, i have to look more deep

lot of people have problems with this issue

http://www.libnfc.org/community/topic/98/mifare-classic-key-recovery-tool-dark-s
ide-attack/page/3/

Original issue reported on code.google.com by romu...@libnfc.org on 18 Feb 2013 at 8:20

[GoogleCodeExporter]

Thanks for the quick response!

I just ran mfcuk again, this time with -v 3 and it seems I may have a slightly 
different issue at hand after all. My "diff Nt" and "auths" are not as equal as 
they were in issue 25.

    $ mfcuk -C -R 0:A -d ffffffffffff -s 250 -S 250 -v 3
    ...
    -----------------------------------------------------
    Let me entertain you!
        uid: 4dad819a
       type: 08
        key: 000000000000
      block: 03
    diff Nt: 84
      auths: 484
    -----------------------------------------------------

Original comment by h.san...@gmail.com on 30 Jan 2014 at 2:55

[GoogleCodeExporter]

I don't have many explanations for this. But from what i know, the error you 
get : "ERROR: mfcuk_key_recovery_block()", i've seen it sometimes when mfcuk 
had all 8 variations of data corresponding to a single nonce but fails to 
recover the key. It then goes on and try recovering the key with another nonce. 
I'd suggest you to try with other -s/-S values (even defaults) and see if you 
ever recover the key.

If you still can't recover the key, you should maybe try with another tag if 
possible (from an other manufacturer i mean). You can also try with a previous 
version of mfcuk (i'd suggest r65 with libnfc 1.5.1).

If you have the same error, well, i don't know what else it can be. Anyway, i 
think it should be discussed in another issue as it is unrelated to this one.

Original comment by algar...@gmail.com on 7 Feb 2014 at 2:10

[GoogleCodeExporter]

Hi,

Please send me r65 version via email or let me how to get its source.  I can 
not find it in Downloads section. (mfcuk-0.3.3 is not present)

Thanks in advance.

Original comment by yavari....@gmail.com on 16 Mar 2014 at 7:36

[GoogleCodeExporter]

Yavari, in linux you can download it directly from terminal using this command. 

svn checkout -r 65 http://mfcuk.googlecode.com/svn/trunk/ mfcuk-read-only

Original comment by ce.roso...@gmail.com on 21 Mar 2014 at 9:20

[GoogleCodeExporter]

[deleted comment]

[GoogleCodeExporter]

Someone managed to solve the problem of "mfcuk_verify_key_block"? 

I remember a year ago I could compile without this error, and could run 
normally, the problem could be an update of some lib dependency? 

Already tried on two different computers with Ubuntu and the same problem 
happens when compiling and when running this.

Original comment by acassio....@gmail.com on 31 Mar 2014 at 4:53

[GoogleCodeExporter]

hello all, I have a  problem, how install revision 94 in kali linux? 
please I need help!! 
please!

Original comment by felipeig...@gmail.com on 11 Jul 2014 at 12:10

[GoogleCodeExporter]

To get this working on Kali, download the mfcuk.c file from 
https://code.google.com/p/mfcuk/source/browse/trunk/src/mfcuk.c.

Then run through this process 
http://docs.kali.org/development/rebuilding-a-package-from-source and make sure 
to replace the mfcuk.c file in the src directory with the one you downloaded.

When you get to the bit where you need to run dpkg-buildpackage, add -b to the 
command or it will fail. So the command is dpkg-buildpackage -b.

Original comment by cherryd...@gmail.com on 26 Sep 2014 at 11:13

[GoogleCodeExporter]

Alternatively, here's the deb file with the fix implemented for 64 bit 
architecture, just install with dpkg -i mfcuk_0.3.8-0kali3_amd64

Original comment by cherryd...@gmail.com on 26 Sep 2014 at 11:54

Attachments:

• mfcuk_0.3.8-0kali3_amd64.deb

[GoogleCodeExporter]

Hi all,

I've an so called "Eurest à la Carte" Prepaid card for our cantine and my plan 
was to build a little App which shows us the current charge. But I can't get 
the Key A of sector 9-12. mfoc didn't got the key and same for mfcuk. I tried a 
lot of versions all with the same results:

screen mfcuk -C -R 9:A -v 3
...
-----------------------------------------------------

-----------------------------------------------------
Let me entertain you!
    uid: f2dfe2dd
   type: 08
    key: 000000000000
  block: 27
diff Nt: 65535
  auths: 65536
-----------------------------------------------------

-----------------------------------------------------
Let me entertain you!
    uid: f2dfe2dd
   type: 08
    key: 000000000000
  block: 27
diff Nt: 65536
  auths: 65537
-----------------------------------------------------
mfcuk: ERROR: mfcuk_key_recovery_block() (error code=0x09)

-----------------------------------------------------

I killed the tool at this point, I think it makes no sense to keep it running, 
isn't it?

So it could be possible that there are a lot of cards in circulation with fixed 
random generator or whatever...

BR
Daniel

Original comment by samsung....@googlemail.com on 16 Dec 2014 at 8:15

[GoogleCodeExporter]

As I see from a lot of discussion in the WEB, mfcuk doesn't work any more? 

Original comment by jons...@gmail.com on 7 Jan 2015 at 9:43