Powers of Tau Operational Writeup

Round: 25
Date: 2017-12-15
Name: Fabrice Marchal
Location: Paris, FR

BLAKE2b (challenge) = 5e082983f7b07fefeff1303209caeb9eccaa1ccd5ec365d09cdcb413b9f9fecfd85f79c577028e67efd9ff1f062c8b603b65a6e5ed51b98bd477704a1341034d BLAKE2b (response) = b39c2f54485df51cd0434b0d3cbfcff7b7cc02c2e941097526cf5e605c9f8aaddd3cf9372d0e567cad8c49d7b507a47dac7510203a7f2f00b7d7810636064f06

- Binaries and packages used to create response file
- Some pictures

Preparation steps

Git repository: https://github.com/ebfull/powersoftau
Commit hash: d47a1d3d1f007063cbcc35f1ab902601a8b3bd91
powersoftau-master-d47a1d3.zip : SHA256 = 0902301defc0705d3d824d9ec17382f40785cb9ce84502ee13b774840752def7 rust-1.21.0-1.fc27.x86_64.rpm : SHA256 = c4abe782505c90232fa65eb6f3de550cf3068cc3f4ba8dfeeb3a4967fc783aea cargo-0.22.0-1.fc27.x86_64.rpm : SHA256 = 078b1292716488af6b96494a581726565c24e41b913a424b7a2fbfdf73ccb613 Fedora-Workstation-Live-x86_64-27-1.6.iso : SHA256 = d242345fa6b5f8cc80e2317c46d15bb1fc4ad70b9a3516c9bc2fb6f3599c8117

I burned 3 DVD-R with all needed software :
1) Fedora 27 Live DVD
2) compute binary (build by myself) and brasero software
3) challenge file

Sidechannel Defences

I tried to make a rudimentary faraday cage with aluminum foil all around the airgap compute node. The compute node was plug only to the screen, keyboard, mouse and DVD reader. The compute node is a spare Dell precision T3610 already used before. I removed hard drive and speaker. There was no wifi or bluetooth chip inside. All the computing process was done on RAM and i run 1 pass of Memtest before and 2 passes after. I was alone in my flat(except my cat) during the compute process with no device around the compute node.

I downloaded Fedora iso and challenge file on my daily computer and i burned then into DVD-R media.

I booted the airgap compute node, on Fedora Live DVD and I created a ramfs partition to store compute binary and challenge file.
I enter some text to provide additional entropy as requested :
- License plate of random cars in the street
- Words taken randomly in one book on my desk
- Random type on keyboard

Computing process took around 1 hour.

I burned a 4th DVD-R with response file and I inserted it inside my daily computer to upload it.

The BLAKE2b hash of `./response` is:
        b39c2f54 485df51c d0434b0d 3cbfcff7
        b7cc02c2 e9410975 26cf5e60 5c9f8aad
        dd3cf937 2d0e567c ad8c49d7 b507a47d
        ac751020 3a7f2f00 b7d78106 36064f06

I destroyed the 4 DVD and i run a complete Memtest on compute node, 2 passes.

I did not destroy the computer or hardware inside but i won't used it until 1 month and it will be unplugged from power source.


Le 14-12-2017 08:34, Fabrice MARCHAL via zapps-wg a écrit :

Hi Sean,
I mean this week (15/12, 16/12, 17/12) and next week (22/12, 23/12, 24/12).


Le 14 décembre 2017 05:51:35 GMT+01:00, Sean Bowe <s...@z.cash> a écrit :

Absolutely! By "next Friday, Saturday or Sunday" do you mean over the
next 3 or 4 days or next week?


On Wed, Dec 13, 2017 at 12:15 PM, Fabrice MARCHAL via zapps-wg
<zapps...@lists.z.cash.foundation> wrote:

I would like to participate in MPC.

My compute node is ready and i fully tested the computing process.

Let me know if you need more information about my process or about me before
to participate in MPC.

If nobody is in line i can be the next, i'm able to do this on next Friday,
Saturday or Sunday.

Thank you


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