6 ms·

I wasn't able to automate the use of the freeze spray alas, but I believe that did let me access data after more significant durations. With the freeze spray I

I wasn't able to automate the use of the freeze spray alas, but I believe that did let me access data after more significant durations. With the freeze spray I did also manage to unplug the power cable completely and switch SD cards manually. Edit: In "Cold Boot Attacks are Still Hot: Security Analysis of Memory Scramblers in Modern Processors" they say "To assess the feasibility of cold boot attacks on today’s denser and smaller components, we measured the retention time of ﬁve DDR3 and two DDR4 modules from various manufacturers. At normal operating temperatures, a signiﬁcant fraction of the data is lost within 3 seconds of losing power." The Pi 4 I used makes use of DDR4 from what I recall.

yonatan8070 3y ago
What results would you expect to get if you simply put the whole setup in a regular freezer? Or if you just tried it during winter
- anfractuosity 3y ago
  It sounds like a typical freezer cools to around -20C, I think the freezer spray I used directly on DDR chip, claims to chill to around -50C, but not sure how much the surface temperature decreases after spraying and how fast it warms up again.
  - jacquesm 3y ago
    Industrial freezers will go to -45, lab freezers to -85 before getting into really exotic stuff.
    - azalemeth 3y ago
      LN2 is 77 K (-196 ºc) and dirt cheap -- cents/pence per litre. Most electronics works surprisingly well in it, at least until it warms up and the condensation starts to be a problem ;-).
      - TeMPOraL 3y ago
        What about the material physics of losing some 220°C in a second? Won't things crack from this alone?
        azalemeth 3y ago
        That's an excellent question and as you rightly highlight depends on things like ∂T/∂t that are perhaps a bit harder to control In practice, however, most electronics is fine (!) with the right materials – even a relatively bog-standard gaming CPU [1]... [1] https://www.youtube.com/results?search_query=ln2+overclocking https://www.youtube.com/results?search_query=ln2+overclockin...

yonatan8070 3y ago

What results would you expect to get if you simply put the whole setup in a regular freezer? Or if you just tried it during winter

anfractuosity 3y ago
It sounds like a typical freezer cools to around -20C, I think the freezer spray I used directly on DDR chip, claims to chill to around -50C, but not sure how much the surface temperature decreases after spraying and how fast it warms up again.
- jacquesm 3y ago
  Industrial freezers will go to -45, lab freezers to -85 before getting into really exotic stuff.
  - azalemeth 3y ago
    LN2 is 77 K (-196 ºc) and dirt cheap -- cents/pence per litre. Most electronics works surprisingly well in it, at least until it warms up and the condensation starts to be a problem ;-).
    - TeMPOraL 3y ago
      What about the material physics of losing some 220°C in a second? Won't things crack from this alone?
      - azalemeth 3y ago
        That's an excellent question and as you rightly highlight depends on things like ∂T/∂t that are perhaps a bit harder to control In practice, however, most electronics is fine (!) with the right materials – even a relatively bog-standard gaming CPU [1]... [1] https://www.youtube.com/results?search_query=ln2+overclocking https://www.youtube.com/results?search_query=ln2+overclockin...