TC1 counts the number of TC0 overflows (carry bits).
In random conditions TC1 would return or stay at zero,
instead of counting up. This due to the behavior of the
reset signal.
SAM7S Series Datasheet, 33.5.6 Trigger:
Regardless of the trigger used, it will be taken into account
at the following active edge of the selected clock. This means
that the counter value can be read differently from zero just
after a trigger, especially when a low frequency signal is
selected as the clock.
The new code first prepares TC1 and asserts TC1 trigger and
then prepares TC0 and asserts TC0 trigger. The TC0 start-up
will reset TC1.
This makes the PM3 generate pseudo-random nonces rather than sequential
nonces, to make it act a bit more like a "real" MFC card. A reader would
otherwise be able to detect the PM3 probing based on the predictable nonces
and throw different authentication challenges (or refuse to authenticate at
all).
The code includes an implementation of a rand-like function (prand), similar
to the one from libc, which is seeded automatically based on the time it
takes between the PM3 starting up and the first call to the RNG.
This isn't cryptographically random, but should be "good enough" to be able
to evade basic detection.
- enhanced tracing: hf 14a list now shows meaningful timing information. With new option f it also shows the frame delay times (fdt)
- small fix for hf 14b list - it used to run into the trace trailer
- hf 14a sim now obeys iso14443 timing (fdt of 1172 or 1234 resp.)
Note: you need to flash FPGA as well.
More details in http://www.proxmark.org/forum/viewtopic.php?pid=9721#p9721
2. emulator commands select, authenticate, read block, write block works
3. nested authentication - not working (maybe next release)
4. small bugfixes
5. mifare1ksim - in alpha state!!! code not so clear!!!
1. commands changed from "hf 14a" to "hf mf"
2. some code cleaning and small bugfixes
3. alpha version hf mf sim
4. added internal function GetTickCount() for time measuring
I have kept whatever copyright notices exist. Please add your own
copyright notice if you have made any nontrivial changes or additions to
the code. There are several files without any attribution, currently.
