Date: Mon, 4 Jan 2021 15:15:21 +0100 From: Solar Designer <solar@...nwall.com> To: john-users@...ts.openwall.com Subject: Re: Cracking rar password with rar-opencl Hi Anton, On Mon, Jan 04, 2021 at 11:55:52AM +0100, Anton Berggren wrote: > Device #0 (1) name: Intel(R) HD Graphics 4600 > Device #1 (2) name: Intel(R) Core(TM) i5-4670K CPU @ 3.40GHz This embedded GPU is of comparable performance to the CPU. Here's i7-4770K under Linux: $ ./john -test -format=rar-opencl -dev=1 Will run 8 OpenMP threads Device 1: Intel(R) HD Graphics Benchmarking: rar-opencl, RAR3 (length 5) [SHA1 OpenCL AES]... (8xOMP) Build log: fcl build 1 succeeded. fcl build 2 succeeded. bcl build succeeded. LWS=16 GWS=640 (40 blocks) DONE Raw: 680 c/s real, 96000 c/s virtual $ ./john -test -format=rar-opencl -dev=2 Will run 8 OpenMP threads Device 2: Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz Benchmarking: rar-opencl, RAR3 (length 5) [SHA1 OpenCL AES]... (8xOMP) Build log: Compilation started Compilation done Linking started Linking done Device build started Device build done Kernel <RarInit> was not vectorized Kernel <RarHashLoop> was successfully vectorized (8) Kernel <RarFinal> was successfully vectorized (8) Kernel <RarCheck> was not vectorized Done. LWS=128 GWS=1024 (8 blocks) DONE Raw: 459 c/s real, 57.8 c/s virtual $ ./john -test -format=rar Will run 8 OpenMP threads Benchmarking: rar, RAR3 (length 5) [SHA1 256/256 AVX2 8x AES]... (8xOMP) DONE Raw: 512 c/s real, 64.5 c/s virtual Please note that rar-opencl also makes some use of the CPU via OpenMP, even when its target device is a GPU. You'll probably want to run similar tests for all 3 of your devices, and perhaps post the results in here. > And i resume with this command and get the output > C:\Users\Anton\Downloads\john-1.9.0-jumbo-1-win64\run>john --restore > Device 3: GeForce GTX 760 > Loaded 1 password hash (rar-opencl, RAR3 [SHA1 OpenCL AES]) > Will run 4 OpenMP threads > Proceeding with incremental:ASCII > Press 'q' or Ctrl-C to abort, almost any other key for status > > Is it only using my Nvidia GPU? How can i utilize all my decices? Can i > optimize my rar password cracking for a more effective usage? > It seems that my GPU usage isnt constant. It goes up and down.. up and > down.. up and down... about 10-30%. That is what windows reports anyway. Do you mean 10-30% utilization, or 10-30% left idle (so 70-90% load)? The fluctuating utilization is possibly because of post-processing done on the CPU. How large is the RAR archive? You might increase average GPU utilization by running more than one attack on it - either start a second instance of JtR with a different "--session" name and configured to test different candidate passwords (a non-overlapping wordlist, etc.) or use "--fork=2" (yes, with just one NVIDIA GPU device). Using the CPU more directly and using its embedded GPU isn't necessarily a good idea as it'd likely lower your NVIDIA GPU utilization, but feel free to give this a try with separate sessions. You'll likely want to set a lower CPU thread count via the environment variable OMP_NUM_THREADS to reduce competition for the CPU (competition can be very wasteful). Using all devices in one session (like you technically could with "--devices=1,2,3 --fork=3" is almost certainly a bad idea since the devices are so different and since the best way to use a CPU is generally by using the non-OpenCL format, but feel free to try anyway. (Maybe I'm over-estimating your NVIDIA GPU's performance, and it's actually similar to your CPU and your embedded GPU? I notice it's a Kepler era device, and isn't large.) Again regarding the fluctuating GPU utilization, see also the "rar-opencl performance" thread we had in here in September: https://www.openwall.com/lists/john-users/2020/09/ Windows might be under-reporting GPU utilization. We recently had a thread in here where this was found to be the case for AMD GPUs. For more reliable reporting, please use tools that come with the GPU driver. Anyway, far more importantly than all of the above, you need to focus the attack to test candidate passwords that are actually likely. You might want to share in here what you know/recall about the password in plain English, and we'll help you encode that into options to "john". Alexander
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