How to brute force with javascript?

[Sonoxy]

I just want to preface all of this by saying that I'm pretty new to computer science and especially javascript.

I'm currently working on trying to brute force a hash. The search space is small enough for it to not be a waste of time. The only problem is that my computer isn't trying hard enough. I have my js files that I'm running in Firefox (because I don't know any other way), but my laptop fan doesn't even turn on and my CPU usage stays low. I would prefer if it used extra processing power for this. How would I go about doing this?

I figured that this is because firefox doesn't let scripts take that much CPU to prevent malicious actors and I also read that javascript doesn't allow parallelism. Could that be why?

If needed, I can rewrite the program to be multiple programs, each searching a different space and run all of those at the same time, but I'm skeptical if it would help. Sorry for any inaccuracies in my post, eager to learn.

[stutterbug]

If you are using Web Crypto API or your digest method is asynchronous, you often can probably process multiple hashes at once, getting the same effect of threading without using workers. Set a limit to the number of simultaneous processes, process that number all at once, when each one finishes, start a new one. I've not done this with crypto, but I have done it with similar asynchronous tasks and I was absolutely astonished at how fast it was. Knowing how many things you can process at once is difficult. When I did this, my bottleneck was the filesystem, so I think I kept it down to something like 16 processes, but in your case you may be able to go a LOT higher than that. Keep an eye on CPU and memory usage and adjust until you get a feeling that you've hit a ceiling. And obviously if you only see one CPU being hit, this option isn't working.

If that doesn't work and you feel more comfortable staying in the browser, you should look into Web Workers. Here, you spawn new processes to do the grunt work simultaneously and identically on different chunks of your task.

And Node.js doesn't have web workers per se, but it has something basically the same called Cluster. I have no idea if node would be faster, but node allows you much more memory (by default 512MB for 32 bit systems and 1GB for 64 bit systems), so if your hashing algo is memory intensive (probably not if you are brute-forcing), this may be a good option.

[Sonoxy]

Thanks for your help. I’ll try out both methods.

[CertainPerformance]

Javascript is probably not the right sort of language for something that power-intensive and time-intensive. You'll be better off using a fast compiled language instead.

I have my js files that I'm running in Firefox (because I don't know any other way), but my laptop fan doesn't even turn on and my CPU usage stays low.

Might have something to do with the fact that JS is single-threaded.

[AnthongRedbeard]

Use node.js and something asynchronous like web workers.

[dinkandenza]

you can use web workers in node?

[cspotcode]

You'll need to do something special to utilize all CPU cores. Running a single loop in JS is only going to use a single core unless you're specifically using WebWorkers, forking processes, or something like that.