question about wpa wordlist and other things

[wing23]

Hey all

first I want to thank Atom for his work and also time to answer so many questions here on the forum

I'm kinda new in the backtrack/hashcat/WPA world, but I don't feel awkward being a n00b
anyway, I played around with aircrack and stuff, then finally found oclhashcat-plus while googling some questions that came up while I experimented with backtrack.

using a virtual machine that's limited by software I achived around 4100 c/s on my cpu. Using my video card is not possible on the virtual machine. I found oclhashcat-plus and wow, I was able get up to 117k c/s, played around with the resource options (I use the GUI) it even went up to 145k c/s!

So, now I've got some questions:
My card is a XFX HD7970, I use newest Radeon (I know you suggest an older driver).
I googled a lot to find out what is best to set for workload tuning and gpu loops and segment size but all I found was a hint to increase these values to make it faster.
But what are the correct/best settings?

I don't see any big difference between 512 loops and 4096.
I set workload tuning to 80.
I also don't notice any difference between 32 MB segment size or 128 MB. Does this option just decrease HDD access to the word list?

now the next question is: what does it mean when hashcat rejects keys from the word list? shouldn't it try every line of the word list?
Using the 13 gig word list gives me 0 rejects, using the darkc0de list results in around 33% rejects.

The max keylength of 16 is just for bruteforce, right?

I tried to crack the key of my router. I got a handshake and converted the cap file to hccap using aircrack -J
I then made a dictionary that contains just my key.
hashcat processes it but the result ist "exhausted", it doesn't find it!

my main question is: what am I doing wrong?

thanks a lot for any advice!

[KT819GM]

First wrong thing that you don't read wiki:

wiki

Where is written:

Code:

Password-length is set to a maximum of 15 on all algorithms

[wing23]

ahhh I somehow ignored the "all"
hmm then the "rejected" must mean something else
I thought the rejected means >15 or >16 chars, so I put my key into it's own dictionary and it wasn't rejected

anyway, is there a reason for the limit?

[undeath]

allowing greater lengths would cause a worse performance and probably more coding.

[atom]

The tuning parameter is not just to make it faster, its also to make it slower if you wish to. For example if I want to play a game or watch a movie while cracking i need to reduce the GPU utilization from cracking down to ~96% to play with full fps

[wing23]

I see
but it's just possible to use fix values, right?
I read something like 1, 20, 40, 80 and 160 IIRC
but what exactly are gpu loops for, or in other words, why is 4096 suggested for wpa?

[KT819GM]

Check how busy is your GPU with 20 and with 800, if you see no difference (always get ~98% busy) then it means you feed enough work for it and no need to go higher.

[wing23]

ok thanks