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Comment Re:Because 1/0 != 0? (Score 1) 1067

Exception yes, NaN no. NaNs suck. An exception takes you right to the problem, or close to it. NaN spreads over your variables like kudzu, since any calculation involving it results in NaN. Sure it tells you there's a problem, but by the time you see it, half your variables are NaN and you're left trying to figure out where it came from.

Comment Educational Purposes (Score 1) 68

They said it's for educational purposes. The point isn't performance -- you're not getting that from RasPis. The point is either to train people on supercomputer programming or to test supercomputer programs on smaller data sets without using time on a real, expensive supercomputer.

I could see building a smaller scale one of these myself as a way to learn MPI.

Comment Re:Overblown Hyperbole (Score 1) 107

Bluetooth (depending how they implement pairing), CD and synced Android device sound like viable attack vectors. None of them are instant remote control with no action by the owner, but they're all quite usable.

Bluetooth: If it makes you enter a code displayed on the other device to pair, that's more secure. But if the car just displays something like "$DEVICENAME Do you want to pair with this device? [Yes] [No]", it's not really. Either someone will habitually click yes, or can be enticed to through careful choice of the device name.

CD: Pretty straightforward. Hand your enemy a CD when he's about to get into his car. Tell him it's a song, lecture or whatever you wanted him to listen to. CD goes in, malicious file does its thing, car crashes. Sure you could sabotage the car itself, but what car crash investigator is going to think to check the CD that was playing for custom-made viruses?

Paired Android device: Similar deal, but even better. Trick them into installing an app modified to contain malware. They'll have their app and be none the wiser. The malware lets you see when and where he's driving (GPS+accelerometer), and you can then interactively take control of the car when you please. Better still, the malware could erase itself from the phone just after the crash, so even if they think to check for that sort of thing, there will be nothing to find.

Comment Re:Here is the letter Lenovo sent out to everyone (Score 1) 266

This seems awfully late to have bought a T420 new. I got a factory-refurb T440p in July 2014. It came pre-loaded with Windows 8.1, which I still have on it and it has never had Superfish. They also claim that they didn't put Superfish on any ThinkPad branded laptop.

If yours came with it, someone somewhere installed the wrong image or additional-software bundle.

Comment Re:Hardware ICE - JTAG (Score 1) 215

Nah. This scheme is designed with hardware-based attacks in mind. From the sound of it, unless you're going to put taps on the actual CPU die this will fail.

The solution is software. Run it in an emulated CPU and dump the emulated TLB whenever you like. Or, there has to be SOME unencrypted code at the start that finds the key and sets up the rest of the nonsense. I expect this part to be heavily obfuscated using traditional techniques that can be deobfuscated with operand tracing and the like. Reverse this and you have the encryption algorithm and key.

This WILL fail but it'll probably make for a few games that take a while to crack, and a few interesting crackmes.

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