Archive for December, 2013

Researchers crack the world’s toughest encryption by listening to the tiny sounds made by your computer’s CPU

December 20, 2013 Leave a comment

Acoustic cryptanalysis of RSA decryption keys using a parabolic microphone

Security researchers have successfully broken one of the most secure encryption algorithms, 4096-bit RSA, by listening – yes, with amicrophone — to a computer as it decrypts some encrypted data. The attack is fairly simple and can be carried out with rudimentary hardware. The repercussions for the average computer user are minimal, but if you’re a secret agent, power user, or some other kind of encryption-using miscreant, you may want to reach for the Rammstein when decrypting your data.

This acoustic cryptanalysis, carried out by Daniel Genkin, Adi Shamir (who co-invented RSA), and Eran Tromer, uses what’s known as a side channel attack. A side channel is an attack vector that is non-direct and unconventional, and thus hasn’t been properly secured. For example, your pass code prevents me from directly attacking your phone — but if I could work out your pass code by looking at the greasy smudges on your screen, that would be a side channel attack. In this case, the security researchers listen to the high-pitched (10 to 150 KHz) sounds produced by your computer as it decrypts data.

This might sound crazy, but with the right hardware it’s actually not that hard. For a start, if you know exactly what frequency to listen out for, you can use low- and high-pass filters to ensure that you only have the sounds that emanate from your PC while the CPU decrypts data. (In case you were wondering, the acoustic signal is actually generated by the CPU’s voltage regulator, as it tries to maintain a constant voltage during wildly varied and bursty loads). Then, once you have the signal, it’s time for the hard bit: Actually making sense of it.

Acoustic cryptanalysis: CPU instructions

Here you can see the frequency spectrogram of various CPU instructions (down the right hand side)

Without going into too much detail, the researchers focused on a very specific encryption implementation: The GnuPG (an open/free version of PGP) 1.x implementation of the RSA cryptosystem. With some very clever cryptanalysis, the researchers were able to listen for telltale signs that the CPU was decrypting some data, and then listening to the following stream of sounds to divine the decryption key. The same attack would not work on different cryptosystems or different encryption software — they’d have to start back at the beginning and work out all of the tell-tale sounds from scratch.

The researchers successfully extracted decryption keys over a distance of four meters (13 feet) with a high-quality parabolic microphone. Perhaps more intriguingly, though, they also managed to pull of this attack with a smartphone placed 30 centimeters (12 inches) away from the target laptop. The researchers performed the attack on different laptops and desktops, with varying levels of success. For what it’s worth, the same kind of electrical data can also be divined from many other sources — the power socket on the wall, the remote end of an Ethernet cable, or merely by touching the computer (while measuring your body’s potential relative to the room’s ground potential).

A smaller, light-weight acoustic cryptanalysis setup

In this light-weight setup, only the microphone (B) needs to be positioned correctly — everything else could be hidden away, for stealthy snooping

In terms of real-world repercussions, acoustic cryptanalysis is actually surprisingly dangerous. Imagine if you were decrypting some files in a library, coffee shop, or other public space — someone could obtain your decryption key just by placing their phone near your computer. Alternatively, an attacker could use spear phishing to put malware on yourphone that listens for the decryption key. With HTML5 and Flash able to access the microphone, it would be possible to build a website that listens for encryption keys too. The researchers propose one particularly nefarious scenario: Put a microphone into a co-located server, slot it into a rack in a data center, and then scoop up the encryption keys from hundreds of nearby servers.

If you want to keep your data secure, you only really have two viable options: Heavy-duty encryption, physical security, and ideally both at the same time. If an attacker can’t get physically close to your data, it instantly becomes much harder to steal it. As far as mitigating acoustic cryptanalysis attacks, you either implement physical security — keep your laptop in a sound-tight box, or never let anyone near your computer when you’re decrypting data — or you need to use a “sufficiently strong wide-band noise source.” Something like a swooping, large-orchestra classical concerto would probably do it.

Research paper: RSA Key Extraction via Low-Bandwidth Acoustic Cryptanalysis [PDF]



Why Is Google Buying So Many Robot Startups?

December 6, 2013 Leave a comment

Forget robotic product delivery. As usual for Google, I suspect it’s all about the data.



Image : Google-bot – The M1 Mobile Manipulator from Meka, one of several robot companies acquired recently by Google.

Google has quietly bought seven robotics companies, and has given Andy Rubin, the man who originally led the Android project, the job of developing Google’s first robot army. And so, theNew York Times suggests it might only be a few years before a Google robot driving in a Google car is delivering products to your door.

I somehow doubt Google has anything quite so futuristic in mind. I think the effort is quite similar to both Google’s self-driving car endeavor and its Android project. In other words, it’s all about gaining a dominant position in markets where data is about to explode.

Take Google’s self-driving cars. Contrary to common perception, the company didn’t “invent” this technology; most carmakers were already working on autonomous system when Google got involved, and academic researchers had made dramatic recent progress—propelled in large part by several DARPA challenges (see “Driverless Cars are Further Away than You Think”). Google just saw that this was where the automotive industry was headed, and realized that the advent of automation, telematics, and communication would mean a tsunami of data that it could both supply and profit from. Given that many of us spend several hours a day in automobiles, this data could help Google learn more about users and tailor its products accordingly.

Similarly, I suspect Google has recognized that a new generation of smarter, safer, industrial robots is rapidly emerging (see “This Robot Could Transform Manufacturing” and “Why This Might be the Model-T of Workplace Robots”), and it’s realized that these bots could have a huge impact both at work and at home. Whoever provides the software that controls and manages these robots not only stands to make a fortune by selling that software; they will have access to a vast new repository of data about how we live and work.

In this sense, I think Google is being true to its stated mission: “to organize the world’s information”—although it’s worth noting that in an increasingly connected and data-rich world that could mean seeking to organize just about every aspect of our lives. Luckily for Google, it may soon have a robot army to help it keep everything in order.


written by: Will Knight

Categories: Tech Tags: , ,
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