RSA Encryption Cracked Easily (Sometimes)

January 16, 2019 by 2 Comments

A large chunk of the global economy now rests on public key cryptography. We generally agree that with long enough keys, it is infeasible to crack things encoded that way. Until such time as it isn’t, that is. Researchers published a paper a few years ago where they cracked a large number of keys in a very short amount of time. It doesn’t work on any key, as you’ll see in a bit, but here’s the interesting part: they used an undescribed algorithm to crack the codes in a very short amount of time on a single-core computer. This piqued [William Kuszmaul’s] interest and he found some follow up papers that revealed the algorithms in question. You can read his analysis, and decide for yourself how badly this compromises common algorithms.

The basis for public key cryptography is that you multiply two large prime numbers to form a product and post it publicly. Because it is computationally difficult to find prime factors of large numbers, this is reasonably secure because it is difficult to find those prime numbers that are selected randomly.

However, the random selection leads to an unusual attack. Public keys, by their very nature, are available all over the Internet. Most of them were generated with the same algorithm and random number generation isn’t actually totally random. That means some keys share prime factors and finding a common factor between two numbers isn’t nearly as difficult.

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The Embroidered Computer

January 16, 2019 by 2 Comments

By now we’ve all seen ways to manufacture your own PCBs. There are board shops who will do small orders for one-off projects, or you can try something like the toner transfer method if you want to get really adventurous. One thing we haven’t seen is a circuit board that’s stitched together, but that’s exactly what a group of people at a Vienna arts exhibition have done.

The circuit is stitched together on a sheet of fabric using traditional gold embroidery methods for the threads, which function as the circuit’s wires. The relays are made out of magnetic beads, and the entire circuit functions as a fully programmable, although relatively rudimentary, computer. Logic operations are possible, and a functional schematic of the circuit is also provided. Visitors to the expo can program the circuit and see it in operation in real-time.

While this circuit gives new meaning to the term “wearables”, it wasn’t intended to be worn although we can’t see why something like this couldn’t be made into a functional piece of clothing. The main goal was to explore some historic techniques of this type of embroidery, and explore the relationship we have with the technology that’s all around us. To that end, there have been plenty of other pieces of functional technology used as art recently as well, but of course this isn’t the first textile computing element to grace these pages.

Thanks to [Thinkerer] for the tip!

 

This Monowheel Is Bright Orange, And We Want One

January 16, 2019 by 11 Comments

Monowheels are a singular form of transport. Like electric scooters and the Segway, they are remarkably impractical for getting from point A to point B, are expensive to build or buy, and make you look faintly silly as you ride them down the street. However, we’d be hard pressed to find a member of the Hackaday team that wouldn’t at least want a go on one for half an hour. [MakeItExtreme] felt the same way, and built one of their own.

The build starts with a tube bender, used to form 40mm tubing into a continuous circle to form the main wheel. Teflon is then turned to produce several rollers that interface the main wheel to the inner frame. Several small motorbike tyres were cut apart to create the tread to provide some decent grip. Power comes courtesy of a 110cc four stroke engine, allowing this thing to go just fast enough to get the rider seriously injured in the event of an accident. The team reports stability is poor at low speed, but remarkably good once above 30 km/h.

The team did a great job, and we particularly enjoy the bright orange paint scheme and fetching decals that really finish it off well. The monowheel concept is remarkably similar to the diwheel, which we’ve seen applied to old Fords with somewhat terrifying results. Video after the break.

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Brush With The Power Of 3D Printing

January 16, 2019 by 12 Comments

When it comes to 3D printing, functional prints are still few and far between. Sure, you can print a mount for anything, a Raspberry Pi case, but there are few prints out there that are truly useful, and even fewer that are useful while taking advantage of the specific capabilities of a 3D printer.

The Bouldering Brush from Turbo SunShine turns this observation on its head. It’s a useful device for getting the grime, sand, and sweat out of handholds while rock climbing, and it’s entirely 3D printed using manufacturing techniques only 3D printers can do.

If you’re thinking you’ve seen something like this technique before, you’re correct. The Hairy Lion from [_primoz_] on Thingiverse used a fine mesh of bridging to create small fibers of filament emanating from the mane of a lion. While it’s not a gender-neutral print, this is one of the first objects to make it to Thingiverse that truly showcased the sculptural element of many thin fibers of 3D printed filament. With this Bouldering Brush, these fibers become much more useful and even functional. It’s still a great technique, and if you can get your printer set up correctly and the settings correct, this is an awesome print that will easily demonstrate the capabilities of your printer.

Like the Hairy Lion, the Bouldering Brush is two handles that are mostly solid, and fine filaments of extruded plastic connecting these handles. Take the completed print off the bed , cut down the middle of the bristles, and you have a functional, completely 3D printed brush. Just don’t brush your teeth with it.

Plastics: Acrylic

January 16, 2019 by 15 Comments

If anything ends up on the beds of hobbyist-grade laser cutters more often than birch plywood, it’s probably sheets of acrylic. There’s something strangely satisfying about watching a laser beam trace over a sheet of the crystal-clear stuff, vaporizing a hairs-breadth line while it goes, and (hopefully) leaving a flame-polished cut in its wake.

Acrylic, more properly known as poly(methyl methacrylate) or PMMA, is a wonder material that helped win a war before being developed for peacetime use. It has some interesting chemistry and properties that position it well for use in the home shop as everything from simple enclosures to laser-cut parts like gears and sprockets.

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New Contest: 3D Printed Gears, Pulleys, and Cams

January 16, 2019 by 22 Comments

One of the killer apps of 3D printers is the ability to make custom gears, transmissions, and mechanisms. But there’s a learning curve. If you haven’t 3D printed your own gearbox or automaton, here’s a great reason to take the plunge. This morning Hackaday launched the 3D Printed Gears, Pulleys, and Cams contest, a challenge to make stuff move using 3D-printed mechanisms.

Adding movement to a project brings it to life. Often times we see projects where moving parts are connected directly to a server or other motor, but you can do a lot more interesting things by adding some mechanical advantage between the source of the work, and the moving parts. We don’t care if it’s motorized or hand  cranked, water powered or driven by the wind, we just want to see what neat things you can accomplish by 3D printing some gears, pulleys, or cams!

No mechanism is too small — if you have never printed gears before and manage to get just two meshing with each other, we want to see it! (And of course no gear is literally too small either — who can print the smallest gearbox as their entry?) Automatons, toys, drive trains, string plotters, useless machines, clockworks, and baubles are all fair game. We want to be inspired by the story of how you design your entry, and what it took to get from filament to functional prototype.

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The Printed Solution To A Handful Of Resistors

January 16, 2019 by 30 Comments

Resistors are an odd bunch. Why would you have 1.0 Ω resistors, then a 1.1 Ω resistor, but there’s no resistors in between 4.7 Ω and 5.6 Ω? This is a question that has been asked for decades, but the answer is actually quite simple. Resistors are manufactured according to their tolerance, not their value. By putting twenty four steps on a logarithmic scale, you get values that, when you take into account the tolerance of each resistor, covers all possible values. Need a 5.0 Ω resistor? Take a meter to some 4.7 Ω and 5.6 Ω resistors. You’ll find one eventually.

As with all resistor collections, the real problem is storage. With SMD resistors you can stack your reels in stolen milk crates, but for through hole resistors, you’ll need some bins. [FerriteGiant] over on Thingiverse did just that. It’s a 3D printable enclosure that takes all of your E24 series resistors.

The design of this resistor storage solution is a bit like those old wooden cases full of index cards at that building where you can rent books for free. Or, if you like, a handy plastic small parts bin from Horror Fraught. The difference here is that these small cases are designed for the standard length of through-hole resistors, and each of the bins will hold a small 3D printed plaque telling you the value in each bin.

While this is a print that will take a lot of time — [FerriteGiant] spent 100 hours printing everything and used two kilograms of filament — it’s not like through-hole resistors are going away anytime soon. This is a project that you can build and have for the rest of your life, safely securing all your resistors in a fantastic box for all time.