Multitouch tabletop gaming

Reader [Ramon Viladomat] sent in what he has been working on over the last year at the Universitat Pompeu Fabra in Barcelona. Tired of see nothing but zooming map demos, he created a roleplaying game that takes advantage of the reacTable‘s multitouch interface. Along with multitouch, the reacTable also uses tangible fiducial markers to represent objects and as an alternative input method. Embedded above is a video demoing the interface and gameplay (starts at 3:43). The game lets you move your miniature through a virtual world. The surface shows you how far you can move dynamically as your action points regenerate and slowly reveals more dungeon as you discover it. You can pause the action and use gestures to set attack patterns. We really like this demo and would love to see someone build one using a popular tabletop game like Warhammer 40K. Embedded below is a demo of the associated map editor.

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Use the CPU cache to prevent cold boot? No.


Frozen Cache is a blog dedicated to a novel way to prevent cold boot attacks. Last year the cold boot team demonstrated that they could extract encryption keys from a machine’s RAM by placing it in another system (or the same machine by doing a quick reboot). Frozen Cache aims to prevent this by storing the encryption key in the CPU’s cache. It copies the key out of RAM into the CPU’s registers and then zeroes it in RAM. It then freezes the cache and attempts to write the key back to RAM. The key is pushed into the cache, but isn’t written back to RAM.

The first major issue with this is the performance hit. You end up kneecapping the processor when you freeze the cache and the author suggests that you’d only do this when the screen is locked. We asked cold boot team member [Jacob Appelbaum] what he thought of the approach. He pointed out that the current cold boot attack reconstructs the key from the full keyschedule, which according to the Frozen Cache blog, still remains in RAM. They aren’t grabbing the specific key bits, but recreating it from all this redundant information in memory. At best, Frozen Cache is attempting to build a ‘ghetto crypto co-processor’.

We stand by our initial response to the cold boot attacks: It’s going to take a fundamental redesign of RAM before this is solved.

[via Slashdot]

ATtiny breadboard headers


[Alex] was frustrated by the amount of time it took to start prototyping with an AVR ATtiny. To make things easier, he built headers that carry the 8 and 20 pin chips and plug directly into breadboards. The boards include a 6pin ISP header, resonator, pull-up resistor, reset, and blocking caps. The ATtiny2313 version also has a serial connection header. This is a prototype though, and he forgot to route one of the connections. He plans on having a large batch of boards ready for next month.