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My senior design course focused on asynchronous (clock-less) cryptography circuits; after learning of these, I looked into asynchronous general purpose processo
by whoisthemachine 9y ago
My senior design course focused on asynchronous (clock-less) cryptography circuits; after learning of these, I looked into asynchronous general purpose processors, and learned that ARM actually designed an asynchronous processor back in the 2000's [0].
While they've never quite taken off (the extra gates decrease speed and our harder to manufacture), with the recent side-channel attacks on processor pipelines, I've been hopeful that I would see something pop up. Imagine a world where our processors run without a clock!
[0] https://www.eetimes.com/document.asp?doc_id=1299083 https://www.eetimes.com/document.asp?doc_id=1299083
- rcxdude 9y agoWouldn't asynchronous CPUs increase the amount of side-channels? AFAIK in an asynchronous circuit every aspect of the calculation may affect the time it takes to complete.
- whoisthemachine 9y agoThe attacks I'm aware of use processor timings to measure the effects their programs are having. However, because an asynchronous circuit doesn't complete tasks in a reliable cycle, you can't measure how the pipeline is being effected by your program in the same way. You could find new ways to force the processor to act in a reliable manner that you could measure, but that may change quite randomly from processor to processor, or even from moment to moment, depending on external environmental factors.
- deepnotderp 9y agoNope. In fact EMI and differential power analysis based approaches are actually heavily mitigated in asynchronous, as is bus snooping.
- pjc50 9y agoOne of my CS lecturers worked on this: https://www.cl.cam.ac.uk/~rja14/Papers/micromicro2003.pdf https://www.cl.cam.ac.uk/~rja14/Papers/micromicro2003.pdf It turns out that the advantages are not so great as might appear, and the situation gets worse as DRAM delay dominates. Also logic designers are a conservative bunch and getting everyone to replace the industry standard design toolchain is a big ask.
- TickleSteve 9y agoThat was Steve Furbers Amulet (https://en.wikipedia.org/wiki/AMULET_microprocessor https://en.wikipedia.org/wiki/AMULET_microprocessor) He was one of my lecturers at uni, shame not much became of Armulet tho.
- deepnotderp 9y agoShameless plug, we at Vathys run asynchronous: https://youtu.be/4nSn0JhZX18 https://youtu.be/4nSn0JhZX18
- whoisthemachine 9y agoVery cool :)
- deepnotderp 9y agoThanks!