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Hi, |
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|
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On Thu, 4 Oct 2007 20:33:40 +0200 "Liviu Andronic" |
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<landronimirc@×××××.com> wrote: |
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|
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> On 10/4/07, Alan McKinnon <alan@××××××××××××××××.za> wrote: |
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> > On Thursday 04 October 2007, Hans-Werner Hilse wrote: |
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> > > However, it makes sense to clean up memory after having |
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> > > critical data in it -- e.g. a reboot doesn't necessarily clean up |
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> > > RAM. |
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> > |
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> > Yes, this is very true |
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> |
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> BUT |
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> |
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> On 10/4/07, Alan McKinnon <alan@××××××××××××××××.za> wrote: |
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> > Pray tell, how does RAM manage to retain data when the power is off? |
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> |
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> ...and... |
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> On 10/4/07, Volker Armin Hemmann |
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> <volker.armin.hemmann@××××××××××××.de> wrote: |
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> > In practice, after power is cut, everything in ram is lost. |
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> |
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> So, my eternal question, is it realistic for the "lost" RAM data to be |
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> recovered? That is, after system shutdown, does the data still |
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> physically reside on the RAM and can someone with a decent technology |
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> and know-how recover it? In other words, is this a serious breach in |
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> any encrypted system? |
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|
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No, it isn't. Well, I didn't had the full circuit design of today's |
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DRAMs in mind, and yes, since there's the resistor, the capacitor will |
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lose its load (very) soon (/me scratches his head, wasn't there |
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something asymptotically in that graph? But in any way, it would be a |
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difference of very few electrons on the sides of the capacitor) -- |
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that's not a security breach. |
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|
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But: We are talking about _powering_ _off_ the DRAM. You are talking |
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about shutting down. That might be two different things and completely |
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depend on hardware design. Make shure that RAM's gonna get powered off |
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and you're save. So pulling the plug should give you a warm good |
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feeling in that regard. Doing a "sudo halt", however, _might_ have |
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other consequences and we cannot make a general assumption on that. |
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Even pulling the plug might have problems: There's such thing as |
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battery-buffered RAM (although I think they've used it mainly in the |
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pre-Flash era). |
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|
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The thing is: You never can guarantee security, that's absolutely |
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impossible (well, of course you can, but you would automatically be |
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wrong). You can do all your best, but that's about it. Having security |
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is a thing you can falsify, but never verify, since theorys can't be |
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verified without dogmas (and there are no accepted dogmas that would |
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help here). |
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|
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-hwh |
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-- |
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