The Boston Diaries

The ongoing saga of a programmer who doesn't live in Boston, nor does he even like Boston, but yet named his weblog/journal “The Boston Diaries.”

Go figure.

Wednesday, March 12, 2008

Cold Boot Attacks on Encryption Keys

I've never given much thought to just how “dynamic” dynamic RAM is. I remember as a teenager reading up on computer design (back when it involved picking a CPU and designing the motherboard) and one of the darker aspects revolved around keeping the dynamic RAM refreshed else it lose its contents. Granted, all that was involved was ensuring certain pins got hit every unteen µseconds, but ensuring that involved a timing circuit, a counter circuit and synchronization circuit with the CPU.

And it was made clear that if this “refresh cycle” didn't happen, the dynamic RAM would quickly lose its contents to a sea of zeros (there did exist “static RAM,” which didn't need a refresh cycle, and was faster to read and write, but it was hideously expensive, even factoring into account the refresh circuit needed by dynamic RAM).

Never would I expect dynamic RAM to last seconds past power loss, much less minutes.

Boy, was I wrong (link via Xenophilia). This has some severe security implications. Yikes!

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