[A51] Query - Use of Kraken with CPUs

Nikos Balkanas nbalkanas at gmail.com
Wed Mar 26 17:39:20 CET 2014


On Wed, Mar 26, 2014 at 5:12 PM, Joel Eriksson <joel.eriksson at gmail.com>wrote:

> Using CPUs instead of GPUs doesn't make any sense at all, CPUs are a _lot_
> slower than GPUs for these kinds of computations and you would need a
> cluster (i.e much more expensive) to be able to get similar performance.
>
>
You don't need a cluster for a multiprocessing board. Just a
multiprocessing kernel that linux provides. Radeon's GPUs are, to my
knowledge, AMD CPUs, but at lower frequencies. Granted, you don't have a
general kernel running on top of them, but an MP kernel has load balancing
and preemptive multitasking that kraken hasn't. ;-)

But we are in agreement here. If you have a GPU sitting idle, why not take
advantage of it?

To really crush both CPUs and GPUs, you could create an ASIC for it
> instead. I bet that there are A5/1 cracking ASICs out there already, just
> not in the hands of the public AFAIK. Using FPGAs would be a decent middle
> ground.
>

Yeap.


>
> Cheers,
> Joel
>
>
> On Wed, Mar 26, 2014 at 2:22 PM, Nikos Balkanas <nbalkanas at gmail.com>wrote:
>
>>
>>
>>
>> On Wed, Mar 26, 2014 at 1:51 PM, Joel Eriksson <joel.eriksson at gmail.com>wrote:
>>
>>> It will be _a lot_ slower. If you want to have any chance of
>>> intercepting frequency hopping calls (without having receivers constantly
>>> recording everything at each of the possible frequencies) you need to use
>>> GPUs and SSDs. If you don't have to deal with frequency hopping, and don't
>>> have to decipher in near real-time, it doesn't matter as much.
>>>
>>> Regards,
>>> Joel
>>>
>>>
>> In such case, wouldn't it make more sense to have more CPUs on the MB?
>>
>>
>>> On Wed, Mar 26, 2014 at 11:36 AM, Nikos Balkanas <nbalkanas at gmail.com>wrote:
>>>
>>>>
>>>>
>>>>
>>>> On Wed, Mar 26, 2014 at 8:40 AM, Amber and Sarosh <
>>>> amber_sarosh at hotmail.com> wrote:
>>>>
>>>>> Hi All,
>>>>> Can anyone please guide if GPUs are necessary for rainbow table lookup
>>>>> using kraken to find the key to decipher an intercepted communication or is
>>>>> it possible to do this using just CPUs? In case the later is possible how
>>>>> much time it will take approximately?
>>>>>
>>>>>
>>>> GPUs are not necessary, just desirable. If GPUs are missing, kraken
>>>> will still work with A5Cpu.so, but it will be somewhat slower. Assuming
>>>> that during cracking your PC is CPU limited, the benefit should scale
>>>> roughly with your setup ratio of GPU power/CPU power. In reality you will
>>>> run into RAM and table I/O bottlenecks before that. In short it is highly
>>>> depended on your setup ;-)
>>>>
>>>> The idea is, that the easier factor to improve is the CPU, so why not
>>>> do it?
>>>>
>>>> Nikos
>>>>
>>>>> Regards,
>>>>> Naheed, Amber & Sarosh
>>>>>
>>>>> _______________________________________________
>>>>> A51 mailing list
>>>>> A51 at lists.srlabs.de
>>>>> https://lists.srlabs.de/cgi-bin/mailman/listinfo/a51
>>>>>
>>>>>
>>>>
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>>>>
>>>>
>>>
>>>
>>> --
>>> Best Regards,
>>>   Joel Eriksson
>>>
>>
>>
>
>
> --
> Best Regards,
>   Joel Eriksson
>
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