getting MAC failure using osmo-sim-auth for 3G/USIM authentication

[benoit michau]

Hello,
to perform a 3G authentication with a USIM, you need to know the
authentication key K and counter SQN within the USIM.
RAND / AUTN generation is explained in TS 33.102, section 6.3.


2013/3/9 Rupert Lloyd <rupert.lloyd at gmail.com>:
> Good Afternoon,
>
> I am trying to perform USIM/3G authentication using osmo-sim-auth and ran
> into the same problem as Stefanos:
> http://lists.osmocom.org/pipermail/simtrace/2012-November/000406.html
>
> I followed Benoit's advice to view the details as follows (using the inputs
> from the web page):
>
>> rand_bin = stringToByte(a2b_hex('00000000000000000000000000000000'))
>> autn_bin = stringToByte(a2b_hex('ec9320c2c2000000e1dd22c1ad3e2d3d'))
>> u.authenticate(RAND=rand_bin, AUTN=autn_bin,ctx='3G')
>> u.coms()
>
> ['INTERNAL AUTHENTICATE apdu: 00 88 00 81 22 10 00 00 00 00 00 00 00 00 00
> 00 00 00 00 00 00 00 10 EC 93 20 C2 C2 00 00 00 E1 DD 22 C1 AD 3E 2D 3D',
>  'sw1, sw2: 98 62 - undefined status',
>  (152, 98),
>  []]
>
>
> From TS 31.102, section 7.3.1 it looks like this means a MAC failure (0x98
> 0x62)
>
> Can anyone point me to a resource for computing parameters with a valid MAC?
>
> Thanks for your attention,
>
> Rupert