From deep within the laboratory of Edward W. Felten, we bring you the emperor in all his glory:
Contrary to popular assumption, DRAMs used in most modern computers retain their contents for seconds to minutes after power is lost, even at room temperature and even if removed from a motherboard. Although DRAMs become less reliable when they are not refreshed, they are not immediately erased, and their contents persist sufficiently for malicious (or forensic) acquisition of usable full-system memory images. We show that this phenomenon limits the ability of an operating system to protect cryptographic key material from an attacker with physical access. We use cold reboots to mount successful attacks on popular disk encryption systems using no special devices or materials. We experimentally characterize the extent and predictability of memory remanence and report that remanence times can be increased dramatically with simple techniques. We offer new algorithms for finding cryptographic keys in memory images and for correcting errors caused by bit decay. Though we discuss several strategies for partially mitigating these risks, we know of no simple remedy that would eliminate them.
From the archive:
After reading about these notebook search shenanigans I started using filevault and set a screensaver password, and I hope soon to be in a position to afford the seizure of my notebook at a border.
I have FileVault enabled at present on my mac, which i suppose is pretty secure.
My entire home directory is encrypted with FileVault. Assuming FV is secure (i don't really know), what're they gonna do about it?
Lest We Remember: Cold Boot Attacks on Encryption Keys