Date: Mon, 25 Mar 2019 19:48:14 +0100 From: Solar Designer <solar@...nwall.com> To: john-users@...ts.openwall.com Subject: Re: Question about GPU attack modes On Tue, Jan 08, 2019 at 08:26:17PM +0100, Lukas Odzioba wrote: > wt., 8 sty 2019 o 14:37 Matt Weir <cweir@...edu> napisa??(a): > > I apologize since I haven't used JtR much with GPU support, but what > > current attack modes are available using the GPU? Aka is Markov, > > Incremental, wordlist, etc, supported? > > Technically all because we can generate candidates on a cpu and send > them to the gpu to calculate. > It is ok for slow formats but things like raw-* suffer from PCIe > performance bottleneck.. Lukas is correct. > We had some improvements to the mask mode to generate candidates on a > gpu, but I am not sure about its current state. We have on-device mask mode support for (almost?) all fast hash types for which we have OpenCL support at all. Further, such on-device mask support can be used along with a host-provided stream of partial candidate passwords to form a variety of hybrid modes. For example, these are all valid: Test 7-character any printable ASCII strings, with a reasonable number of the mask positions being processed on device (JtR decides host to optimally split the mask between host and device): --mask='?a?a?a?a?a?a?a' Ditto: --mask='?a' --min-length=7 --max-length=7 Ditto, but for range of lengths 1 to 8: --mask='?a' --min-length=1 --max-length=8 Can also use length ranges with more complex masks, where the last mask component would be the one extended to higher lengths: --mask='start?l?d' --min-length=7 --max-length=14 Use the host's incremental mode to test strings of digits in a smart order, then append 3 more digits in a dumber order on device, no specific length (so let incremental mode switch lengths back and forth like it usually does): --incremental=digits --mask='?w?d?d?d' Ditto, but limit this to (total) length of 8 (adjusts incremental mode to only produces length 5 for its portion): --incremental=digits --mask='?w?d?d?d' --min-length=8 --max-length=8 Have the host generate all-lowercase substrings in a smart order, then prepend an uppercase letter and append 3 digits, at least some of this on device: --incremental=lower --mask='?u?w?d?d?d' Read a wordlist on host, apply wordlist rules on host, then append 3 digits on device: -w=word.lst --rules=jumbo --mask='?w?d?d?d' Duplicate words, then append 3 digits on device: -w=word.lst --mask='?w?w?d?d?d' Another way to write that: -w=word.lst --rules=':d' --mask='?w?d?d?d' Test strings consisting of uppercase words, 4 digits (processed on device), then lowercase versions of the same words: -w=word.lst --mask='?W?d?d?d?d?w' And so on. Many of these option names may be abbreviated. I've just tested all of these combinations of options against raw-md5-opencl and made sure the reported speeds correspond to on-device mask being in use. Alexander
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