Richard Lamb <sl...@xtcn.com> writes: >I am honored. Whit has spoken highly about you to me.
Hmm, and I'm honoured that Whit spoke of me :-). >"discern" was the primary concern through sram imprinting accelerated by >radiation (https://ttu-ir.tdl.org/ttu-ir/handle/2346/58641) Ah, OK. So that's not going to be much of an issue compared to the SEU's you'll be experiencing in your crypto with that level of ionising radiation. Given that he's talking about 100kRad of gamma that'll be for space use, what you encounter in a reactor environment will typically be much lower levels, and then there'll also be fast and thermal neutrons (typical gamma rates there are 5/10/15kRad and varying levels of neutron flux, with the mix being 50% gamma and 25% each fast and thermal neutrons). So in the pure-gamma case you detect SEUs and restart, and your real concern is with single event latchup (SEL) or burnout (SEB) because you can't replace the part if it's in low earth orbit (SEL can typically be recovered through a power cycle, SEB can't). Permanent problems are far more likely with neutrons than gamma. Also, imprinting isn't just caused by radiation, it can also happen in things like SRAM due to storing the same value for extended amounts of time. I mention this in my 1996 paper "Secure Deletion of Data from Magnetic and Solid-State Memory", with more detail on what's going on in "Data Remanence in Semiconductor Devices" from Usenix '01. IANAL, but even if someone patented this before the 1996 paper was published, the patent would have expired by now (there's lots of other work in the area, but I think those ones are significant in patent terms because they mention the use of bit-flipping to protect cryptovariables). I think the detection of ionising radiation in HSMs today would be more for fault attacks than imprinting, for most of the public-key cryptosystems if you can glitch the private-key op you potentially leak the private key (ECC stuff is really bad in this regard), so you wouldn't want to bathe the device in radiation, you'd just want a small number of events to glitch the private-key op and leak it. On a related note, I'm currently working on characterising the effects of ionising radiation on crypto, if anyone has any experience with FreeRTOS and doesn't mind working for s**t wages (it's self-funded :-), let me know. Once I get the gamma and neutron traces I'll publish the data so anyone can simulate the effects by replaying the events into a VM. Peter. _______________________________________________ Tech mailing list Tech@cryptech.is https://lists.cryptech.is/listinfo/tech
