Year: 2007

ToorCon 9: Crypto Boot Camp

October 19, 2007 by 3 Comments

[Rodney Thayer] gave a 2 hour seminar on cryptographic technology. It was designed to give the audience a working knowledge for dealing with vendors. He gave some rules of thumb for choosing encryption. In order of preference, when doing symmetric key crypto: use AES with a minimum 128bit key, if not that 3-key Triple-DES, or last RC4 with 128bit key. For hashing: SHA 256 preferred, SHA 1 if you can’t do any better, and MD5 if you can’t SHA. For public key: RSA using at least a 2048bit key. The top choices in these lists were picked because they’ve stood up to years of scrutiny. One major theme of talk was to never roll your own crypto algorithm or buy someone elses. Proprietary algorithms get broken all the time, like the GSM A5 crypto we talked about earlier this year.

Optical Headphone Amp

October 19, 2007 by 8 Comments


It looks like this one’s been out there for a while, but it doesn’t make it any less awesome. [Andrija] built this combination portable DAC/headphone amp. It takes optical audio input, feeds it through an analog devices AD1866 16bit/96khz decoder. After that, the audio is brought up to volume by an op-amp style headphone amp circuit.

Side note: I wrote up a few short notes on the Sidekick LX I got today, if you dig that sort of thing.

Speaker Power Detection Circuit

October 18, 2007 by 7 Comments


This is an interesting way to monitor your speakers. [Keith] put together this speaker line monitor after a commenter requested it on his blog. It’s designed to check for power on the speaker line and drive a logic/led output. Apparently there’s some risk of shorting your amp, so he’s planning to redesign the input stage. Still, it’s neat little hack to keep an eye on things. Personally, I’d just put em on their own class A amp and automate the power switching, but there are plenty of situations where this could be useful.

Home Brewing Beer Brewery

October 16, 2007 by 16 Comments


I saw this last month in Popular Science, but it wasn’t online for a while. This (nearly) all-in-one brewery was built by [John Carnett]. It does everything but requires malt extract for now. It boils wort, cools it for fermenting, delivers the brew to the kegs and most interestingly to me – uses cold plate cooling to cool the beer just before it exits the tap. I’m pretty sure they’re using peltier junctions, but I’d like to know for sure. Props to [Nate] for inadvertently reminding me of the thing when he sent in this effort to brew beer inside a pumpkin!

Electromagnetic Aluminum Can Crushing

October 15, 2007 by 15 Comments


This has been around for a while, but we never covered it – and it’s friggin’ awesome. [jesse] sent in this crusher, but I featured this one due to a sort of draconian copyright notice on the former. The latter also uses some easier to find, hackable parts. They’re both built on similar concepts – use a large bank of capacitors to store up the energy needed, and deliver it in one large pulse to a coil electromagnet. The resulting force lasts for a short time, but is enough to physically crush an aluminum can inward without touching it. Yet another one has some more dramatic examples of crushed cans.