Hashcat and oclHashcat have gone open source | Hacker News Reader

Hashcat and oclHashcat have gone open source

hashcat.net

81 pointsGarbage18 comments

Oh, this switch https://github.com/hashcat/hashcat/blob/master/src/engine.c#...

What is the purpose of this, exactly? I assume it has to be some sort of performance optimization.

Hashcat probably isn't the best model for clean code, since its primary goal is to squeeze every drop of performance it can get.

It's a hardcoded map of int to string. That's a fairly reasonable way of doing it in vanilla C. How efficient it actually is is down to your compiler. And some compilers impose maximum limits on the size of `case` statements..

An alternative would be a precomputed hash table, similar to what `gperf` does. Requires more work in the build system though.

Besides the curious length of the switch, I'm not seeing anything particularly 'bad' about this code .. sort of left wondering what the big deal is? This is perfectly reasonable code.

It doesn't look too terrible, but it looks like it is optimized for speed, not maintainability. I'm assuming that's why there is a lot of repeated code (instead of putting it into a function/loop). The comments are a little spartan.

I've tried hashcat before, but does anyone know if oclHashcat works on Intel GPUs? Specifically the Iris Pro 5200?

Theoretically yes (Intel does support OpenCL in their iGPU drivers), but performance will be mediocre at best. Faster than CPU hashing though.

I assume the OCL means OpenCL, in which case yes, Intel OpenCL support is very good (figures, since they have no GPGPU api of their own).

If you're seriously interested in GPU acceleration, any reason not to spend $150 on a GTX 950 and get ~5x the performance of your Iris Pro 5200?

I'm just playing around with it for fun, not doing anything particularly important. Also, I don't think I can connect a GPU to my Macbook Pro :(

Sure. And it's a no go on a laptop. Though you can probably get a ~5 year old desktop with PCIe for basically free if you ask around friends and relatives. If you ssh into it, no need for a monitor either.

Meh. That's a bit too much work for me.

Well, with Thunderbolt enclosures, you _could_...

http://www.sonnettech.com/PRODUCT/echoexpressse1.html

I am happy :) It would be great if someone(or me) could increase the length limit for sha512 hashes. Thank you.

> the kernel needs to be compiled at run time

Are there examples of other programs that require this?

Any OpenCL/CUDA program for GPGPU would require this. Different GPUs may have different characteristics (core count, available instructions, memory sizes and speeds), that need to be taken into account and can be optimized for. This can only be done when you know the run-time target device, which is only at run-time.

This is the reason why for GPGPU programs, you often supply the kernel/shader as C code or another intermediate representation (vendor-specific assembly), and the final compilation step is done by the GPU driver.

I believe the Varnish cache server generates C code from its config rules and compile a new kernel based in it.

This all rules are optimized binary code that work directly on the data stream instead if having a runtime that applies the rules.

Many template engines do this.

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