Alex Halderman, Seth Schoen, Nadia Heninger, William Paul, Joe Calandrino, Ari Feldman, Jacob Appelbaum, Ed Felten and I released a paper on Thursday about our research on encryption keys that remain in memory even after the computer has been shutdown. The period of data remanence varies dramatically with temperature. We also describe ways to cool down the memory modules using common "canned air" products.

You can read the paper, get access to source code, and some videos explaining our result in more detail here.