How I cracked my neighbor’s WiFi password without breaking a sweat

By Dan Goodin, Ars Technica » Risk AssessmentAugust 28, 2012 at 10:46AM

The four-way handshake, in which a wireless device (STA) validates itself to a WiFi access point and vice versa.

Last week’s feature explaining why passwords are under assault like never before touched a nerve with many Ars readers, and with good reason. After all, passwords are the keys that secure web-based bank accounts, sensitive e-mail services, and virtually every other facet of our online life. Lose control of the wrong password and it may only be a matter of time until the rest of our digital assets fall, too.

Take, for example, the hundreds of millions of WiFi networks in use all over the world. If they’re like the ones within range of my office, most of them are protected by the Wi-Fi Protected Access or Wi-Fi Protected Access 2 security protocols. In theory, these protections prevent hackers and other unauthorized people from accessing wireless networks or even viewing traffic sent over them, but only when end users choose strong passwords. I was curious how easy it would be to crack these passcodes using the advanced hardware menus and techniques that have become readily available over the past five years. What I found wasn’t encouraging.

First, the good news. WPA and WPA2 use an extremely robust password-storage regimen that significantly slows the speed of automated cracking programs. By using the PBKDF2 key derivation function along with 4,096 iterations of SHA1 cryptographic hashing algorithm, attacks that took minutes to run against the recent LinkedIn and eHarmony password dumps of June would require days or even weeks or months to complete against the WiFi encryption scheme.

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Build This Yellow Jacket Trap for Worry-Free Outdoor Soda Sipping [Video]

By Alan Henry, LifehackerAugust 28, 2012 at 08:00AM


If yellow jackets and other wasps still make unpleasant appearances at your backyard events, this pesticide-free wasp trap will take care of the little pests for you, without you having to lift a finger or risk getting stung.

Instructables user thebeatonpath built this wasp trap with a little red wine (we imagine a sugary drink would work just as well, since wasps tend to love sodas), some dish soap, and an empty plastic bottle. The method is similar to this fruit fly trap: just cut off the upper third of the bottle, flip it over so it fits back into the bottle like a funnel, pour some wine in the bottom of the bottle, add some dish soap to break the surface tension, and seal up the sides so the wasps can’t get out. Put the trap near a wasp nest or where you’ve seen them, and the results speak for themselves in the video above.

If you’re planning a Labor Day BBQ or just want to sip a soda outside before the weather turns cold without stinging insects bothering you, this is a simple, no-fuss way to guarantee your comfort—and safety.

DIY Yellow Jacket Bottle Trap | Instructables

Dragon NaturallySpeaking Speeds Up Your Writing, Is Free This Week Only [Dealhacker]

By Whitson Gordon, LifehackerAugust 27, 2012 at 10:30AM

Dragon NaturallySpeaking Speeds Up Your Writing, Is Free This Week OnlyWindows: Dragon NaturallySpeaking is one of the most popular dictation programs out there, and if you’re looking to speed up your typing, it’s available for free all week.

We’ve talked about the benefits of dictation a couple times before, and while it isn’t for everyone, now’s the time to try it out. Dragon NaturallySpeaking is one of the best dictation programs out there, and while it’s usually $100, you can get it this week for free from TigerDirect (well, $40 with two $20 mail-in rebates). If you’ve ever been curious about giving dictation a shot on your Windows machine, grab up this deal while you can. And, if you want the slightly more powerful Premium version, you can grab it for $20 on Newegg right now.

Dragon NaturallySpeaking | TigerDirect via DealNews

Dropbox Rolls Out Two-Step Verification; Use It [Dropbox]

By David Galloway, LifehackerAugust 26, 2012 at 02:00PM

Dropbox Rolls Out Two-Step Verification; Use ItMost security-minded computer users know about Google’s two-step verification process, but now other popular webapps like Facebook, Amazon, and today Dropbox have also added this great way of reducing your chances of being hacked.

To enable Dropbox two-step authentication you’ll need to allow Dropbox to send you a text message with a code or use a mobile authenticator app if you don’t want Dropbox to have your phone number. Either way works fine and enables the “something you have” plus “something you know” steps to help keep you safe.

To get started go to your account settings page on Dropbox, click on the Security tab, and scroll down to the bottom of the page and enable two-step verification. Or just click this link.

Try Two-Factor Verification | Dropbox via BetaNews

So You Say You Want a Sharp Lens

By Michael Johnston, The Online PhotographerAugust 26, 2012 at 11:38AM

I’ve written about this before (this is stock lecture #173), but I thought I’d take another stab at trying to illustrate the difference between lens contrast and lens resolution. These are illustrations only—software analogies of what lenses with these properties might give you. But sometimes, for us visual people, it’s simply easier to see what we’re talking about than to—well, talk about it.

Lens-1

Lens with neither contrast nor resolution (soft focus lens)

Lens-2

Lens with good resolution but low contrast

Lens-3

Lens with good contrast but low resolution

Lens-4

Lens with both adequate contrast and adequate resolution

I had a little trouble here because reducing the JPEGs in size tended to mask the qualities I’m trying to illustrate. (Also because the file I chose turned out not to be critically in focus: SNAFU.) Here are a couple of details to make the last comparison a bit more clear:

Lens-3detail

Contrast without resolution

Lens-4detail

Both

Any of these types of lenses can be pictorially useful. The so-called Pictorialists at the turn of the 20th century prized lenses that had low contrast and low resolution—they were the opposite of us—and eagerly sought out exemplars that had just the balance they sought. Some of them were quite fanatical about it, and argued about which lenses had just the perfect degree of unsharpness with the same vigor with which we pixel-peep today.

Screen Shot 2012-08-25 at 8.01.54 PM

Pictorialist photograph by Clarence H. White, made with a lens that had
low contrast and low resolution. Note how it also masks misfocus!

(This Clarence White photograph was also printed with low contrast, but don’t let that distract you. Not the same thing.)

When Eastman Kodak was developing its famous series of Commercial Ektar large format lenses (in the 1950s, I think), its scientists conducted a series of empirical tests—they showed a large number of prints to a large number of people to find out what technical properties people actually preferred the look of. They found that people liked high contrast but not-so-high resolution, so that’s how they formulated the lenses. Commercial Ektars have a particular rich-but-smooth look that many large format photographers still prize today.

Here’s a link to a photo taken by Peter Lerman with a Commercial Ektar—this might look like it has good resolution to you, but that’s because it was taken with a 4×5-inch camera, preserving all the fine detail it does have. The lens actually has relatively low resolution. But very good contrast.

…Actually, thinking twice, that example might only confuse people, because it also has contrasty lighting, and that’s not what we’re talking about here. Lens contrast has nothing to do with subject brightness range or the overall contrast of the picture/print; it affects microcontrast, not overall contrast. Here’s another example, a picture by Frank Petronio taken with a 14″ Commercial Ektar (Frank’s a TOP reader so I’ll presume to post the picture here hoping he doesn’t mind):

Petronioektar

(Again, the impression of good resolution is a function of the original photograph being made from an 8×10″ negative, and the democratizing effects of JPEG reduction.)

A B&W photographer for most of my life, I agree with Kodak’s test subjects back in the ’50s: I’ve always liked lenses that have better contrast than resolution.

Now, to some extent, these distinctions no longer matter. Lack of sharpness is just not a big problem with most of today’s lenses, and of course various species of perceived “sharpness” can be selected in software after the fact of taking the picture. I’ve written about that before.

For the most part, I will say that I don’t particularly care for “sharp” or “high resolution” photographs. (It fits some pictures aesthetically, but other pictures it just doesn’t, and, these days, more pictures are ruined by being too sharp than are ruined by being too soft.*) Oversharpening is not quite the epidemic it was a few years ago, but its relentless overuse has pushed our perception of “normal” way up the scale. Excessive “sharpness,” especially excessive unsharp masking, can make me feel nauseous (really—it can be a visceral, physical reaction). You might be amused to learn that a fair number of “found” JPEGs that I post on this site I actually de-sharpen first! I personally prefer vivid pictures—and that often requires judicious sharpness that emphasizes analog lens contrast or its software-created equivalent. (It also concerns lighting and tone, but those are other posts.) As with most things in photography, it varies according to the needs of the particular photographer’s style or the particular picture.

Mike

*For those of you who bought Ctein’s $19.95 “big print,” that’s a very sharp picture, but one that I don’t consider too sharp—the sharpness it has is appropriate to it aesthetically in my opinion.

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How to Clean Stainless Steel (Without Breaking the Bank) [Crowdhacker]

By (author unknown), LifehackerAugust 24, 2012 at 05:00PM

How to Clean Stainless Steel (Without Breaking the Bank)So, stainless steel: 90% steel, 10% chromium. Turns out it’s not so stainless. Under certain conditions, gunk and smudges stick, but they don’t have to stick forever. Before you spend tons of money replacing your appliances, the DIYers at Stack Exchange offer affordable tips on keeping steel stain free.

Illustration by Sean Gallagher.

Question:

We have just finished building a house and we have some small stains on a stainless steel door handle.

I was wondering what was the best way to remove them? Unfortunately I’m not sure what’s caused them. They appear to be small “smudges” along the handle.

Originally asked by Ben

Related: “When should you use metal studs?”

Answer: Flitz

Flitz

Use some Flitz. I used to have a tube of the paste that worked really well on stainless knives. I need to pick up some more from the hardware store.

Answered by Doc Walker

Related: “What DIY tests are available to test quality of stainless steel?”

Answer: Isopropyl Alcohol

I use isopropyl alcohol (isopropanol) to remove oily fingerprints, fatty deposits, etc. Works great on the range hood (extractor hood) above my cooktop, which accumulates fatty deposits quite fast.

Answered by Geir S¯rensen

Answer: Barkeeper’s Friend

Barkeeper's Friend

I’m a big fan of Answered by BMitch

Related: “Steel or aluminum roofing for a suburban home?”

Answer: Weiman

Weiman

We have several stainless steel appliances, and little kids that smudge them every day. We have tried dozens of cleaners, and the best we have found is Weiman.

The have several varieties, but we like the one in the aerosol spray can. You can find it anywhere, we get it at the local mega-mart.

Answered by mohlsen


Think you know the fix for stainless steel stains? Have a different DIY question? Bring your expertise to Stack Exchange — a network of Q&A sites on diverse topics from software programming to cycling to scientific skepticism…and plenty in between.