X86 is a high-level language
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X86 is a high-level language
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Re: X86 is a high-level language
#2[deleted]
Re: X86 is a high-level language
#3Every major server ISA is, in this sense, "high level": the ISA is documented, but the microarchitecture isn't, and there are timing-relevant details known only to the manufacturers. Aciicmez famously demonstrated this with a timing attack on the branch prediction cache.
Re: X86 is a high-level language
#4I think it's time to dig this: http://yarchive.net/comp/linux/x86.html
When Linus worked at Transmeta, doing a weird kind of processors and x86 was considered "a charming odity that works well".
Re: X86 is a high-level language
#5I'm not sure what the takeaway from this is.
Don't implement crypto in software, only hardware? Does that cut out algorithm-writers who won't have FPGAs and fabrication available to them?...
Re: X86 is a high-level language
#6I wonder if introducing a sleep that is longer than the computation could conceivably take would work to solve (or at least make it a lot harder to defeat) the actual problem. The failure case where the computation actually is slow enough to matter could be detected and thrown away.
This of course would require a fully async crypto lib..
Re: X86 is a high-level language
#7I'm not sure what the takeaway from this is. Don't implement crypto in software, only hardware? Does that cut out algorithm-writers who won't have FPGAs and fabrication available to them?...
Or perhaps that we need a ISA extension that provides primitives for security-sensitive code. The instructions may be superficially similar to ones we have now, but the guarantees are around properties that enable developers to reason about the security aspects of that code. /quite possibly wishful
Re: X86 is a high-level language
#8I'm not sure what the takeaway from this is. Don't implement crypto in software, only hardware? Does that cut out algorithm-writers who won't have FPGAs and fabrication available to them?...
Anecdotally, this is the U.S. government's infosec philosophy. Software crypto is looked down on as a toy. "Real" security applications use hardware crypto (smart cards, HSMs, other ASIC-based crypto).
The civilian world might need to catch up.
Re: X86 is a high-level language
#9I wonder if introducing a sleep that is longer than the computation could conceivably take would work to solve (or at least make it a lot harder to defeat) the actual problem. The failure case where the computation actually is slow enough to matter could be detected and thrown away. This of course would require a fully async crypto lib..
If the sleep were cryptographically random, I can imagine it working out actually. But I wouldn't approach the subject unless I were more confident in my knowledge of cryptography.
Re: X86 is a high-level language
#10I wonder if introducing a sleep that is longer than the computation could conceivably take would work to solve (or at least make it a lot harder to defeat) the actual problem. The failure case where the computation actually is slow enough to matter could be detected and thrown away. This of course would require a fully async crypto lib..
The timing is a signal, and you're proposing to mask that signal by adding noise. This does work, but you can work around it by gathering more samples and averaging out the noise. You increase the work required from an attacker, but it's not insurmountable.