Solution Against Cold Boot Attack In the Making 260
Bubba writes "I just discovered this blog: Frozen Cache. It describes a concept for preventing cold boot attacks by saving the encryption key in the CPU cache. It is claimed that by disabling the CPU cache the key will remain in cache and won't be written to memory. The blog says they're working on a proof-of-concept implementation for Linux. Could this really turn out to be a working solution?" Update: 01/19 20:26 GMT by KD : Jacob Appelbaum, one of the authors of the cold boot attack paper, wrote in with this comment: "It's not a solution. It simply seeks to make it more obscure but an attacker would certainly still be able to pull off the attack. From what is on that blog, there's still a full keyschedule in memory at this time. This is how we reconstruct the key, the redundant information in memory; it's not just the 128/256 bit key itself. For older methods, they needed the actual specific key bits but we don't need them because we recreate them. Basically, the CPU is acting as a ghetto crypto co-processer. Emphasis on ghetto. It's a nice suggestion but the devil is in the details and sadly the details in this case aren't really up to snuff. It's a bogus solution."
Freeze the CPU (Score:5, Insightful)
a hack on a hack (Score:4, Insightful)
br/>Sounds like a tiny back door fix with a hell of a cat flap in it.
I don't understand... (Score:4, Insightful)
Wasn't the "secure computing" preached by Intel/MS and others a "secure" platform that would solve all the security issues?
To me seams that it was only a farse to disguise DRM into everyones computers...
And fail...
Re:Easier (Score:3, Insightful)
Yes, but the benefit of a cold-boot attack is that the data is just there; you don't need to remove the DIMMs and read tiny electrical fields with special machinery; you just read the bytes.
There is no CPU instruction for *any* architecture that will give you the voltage level of a memory cell.
Re:A safer alternative (Score:4, Insightful)
Re:Write a summary that's useful, kthx. (Score:5, Insightful)
Re:Freeze the CPU (Score:5, Insightful)
Thus, if the attacker has physical access to your box, you're screwed!
Re:Freeze the CPU (Score:5, Insightful)
Sorry, flop == flip-flop.
Re:Freeze the CPU (Score:3, Insightful)
Re:Freeze the CPU (Score:3, Insightful)
Carefully repowering SRAM can maintain the contents. I have seen SRAM come up with essentially 99% of the contents still intact after the SRAM had been powered down for over a week. I guess that once powered up, the SRAM has a preference to come back the way it was before powerdown. Or perhaps the slight residual voltage kept the SRAM contents intact. (Even though it was probably less than one tenth of a volt.) SRAM draws very little current when the voltages are reduced. Thus the power rails can maintain some small voltage for a very long time. .
I would really like to see any citation to support your point. If true, this is really an interesting concept.