oclHashcat for AMD v1.30 slow with "mask"
#1
Hi.

In case you run a brute force with mask, speed decreases.
oclHashcat32.exe -m 0 -a 3 8fa1c84f6XXXX38ccXXXXf04274a0c52 ?a?a?a?a?a?a?a?a?a?a?a?a
Speed.GPU.#1...: 1108.5 MH/s

oclHashcat32.exe -m 0 -a 3 8fa1c84f6XXXX38ccXXXXf04274a0c52 ?a?a?a?a?a?a?a?akeys
Speed.GPU.#1...: 992.8 MH/s

oclHashcat32.exe -m 0 -a 3 8fa1c84f6XXXX38ccXXXXf04274a0c52 keys?a?a?a?a?a?a?a?a
Speed.GPU.#1...: 10220.0 kH/s



Why does my search mask keys?a?a?a?a?a?a?a?a well as speed decreases?
Thank you for your help.
================
E6600 + ATI5670
#2
Because you lose the amplifier. That's very technical and goes back how oclhashcat partially reverses the MD5. The best workaround is to use it as a salted hash:

oclHashcat32.exe -m 20 -a 3 8fa1c84f6XXXX38ccXXXXf04274a0c52:keys ?a?a?a?a?a?a?a?a

That'a slower as it can not reverse anymore, but should be faster than 10220.0 kH/s
#3
(08-28-2014, 06:05 PM)atom Wrote: Because you lose the amplifier. That's very technical and goes back how oclhashcat partially reverses the MD5. The best workaround is to use it as a salted hash:

oclHashcat32.exe -m 20 -a 3 8fa1c84f6XXXX38ccXXXXf04274a0c52:keys ?a?a?a?a?a?a?a?a

That'a slower as it can not reverse anymore, but should be faster than 10220.0 kH/s

I was doing something like this today with NTLM I specified a few character of the known password and the rest was a mask and that resulted in significantly slower processing.

Is this due to something similar?

Code:
./hc -w 3 -a 3 -m 1000 ntlm.wrk M?s?l?l?l?s?d?d?d?d
#4
yes, same case, but there's no salted version of NTLM as this algorithm isn't used in a generic case. for ntlm, the only way to solve this is to produce 2 half dictionaries using maskprocessor and then use in -a 1 mode:

using the data from above example it would look like this:

mp64.bin -o d1 keys?a?a?a?a
mp64.bin -o d2 ?a?a?a?a

oclHashcat32.exe -m 1000 -a 3 8fa1c84f6XXXX38ccXXXXf04274a0c52 -a 1 d1 d2