[tor-dev] [RFC] Proposal: A First Take at PoW Over Introduction Circuits

[George Kadianakis]

George Kadianakis <desnacked at riseup.net> writes:

> tevador <tevador at gmail.com> writes:
>
>> Hi all,
>>

Hello,

I have pushed another update to the PoW proposal here:
  https://github.com/asn-d6/torspec/tree/pow-over-intro
I also (finally) merged it upstream to torspec as proposal #327:
  https://github.com/torproject/torspec/blob/master/proposals/327-pow-over-intro.txt

The most important improvements are:
- Add tevador as an author.
- Update PoW algorithms based on tevador's Equix feedback.
- Update effort estimation algorithm based on tevador's simulation.
- Include hybrid attack section.
- Remove a bunch of blocker tags.

Two things I'd like to work more on:

- I'd like people to take tevador's Equix PoW function and run it on
  their boxes and post back benchmarks of how it performed. Particularly
  so if you have a GPU-enabled box, so that we can get some benchmarks
  from GPUs as well. That will help us tune the proposal even more.

  For my laptop (with an Intel CPU i7-8550U CPU @ 1.80GHz) I got pretty
  accurate benchmarks (compared to https://github.com/tevador/equix#performance):
  $ ./equix-bench 
     Solving nonces 0-499 (interpret: 0, hugepages: 0, threads: 1) ...
     1.910000 solutions/nonce
     283.829505 solutions/sec. (1 thread)
     22810.327943 verifications/sec. (1 thread)
  $ ./equix-bench --threads 16
     Solving nonces 0-499 (interpret: 0, hugepages: 0, threads: 16) ...
     1.910000 solutions/nonce
     2296.585708 solutions/sec. (16 threads)
     20223.196324 verifications/sec. (1 thread)

  See how to do this here: https://github.com/tevador/equix#build

- I'd like to improve the effort estimation algorithm by dynamically adjusting
  SVC_BOTTOM_CAPACITY instead of having it as a static value. Otherwise, I
  would like to reduce the currently suggested SVC_BOTTOM_CAPACITY because I
  feel that 180 is too big. I would like to put it to 100 which is much more
  conservative.  I tried to do so while updating tevador's simulation
  accordingly, but I found out that the simulation code does not do the graphs
  itself, so I didn't make much progress here.

  tevador do you have the graphing code somewhere so that I can run the
  experiments again and see how the graphs are influenced?

Apart from that, I think the proposal is really solid. I have hence merged it
as proposal #327 to torspec and further revisions can be done on top of that
from now on.

Thanks for all the work here and I'm looking forward to further feedback!