87 lines
3.7 KiB
Plaintext
87 lines
3.7 KiB
Plaintext
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA256
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Powers of Tau Operational Writeup
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=================================
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Round: 25
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Date: 2017-12-15
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Name: Fabrice Marchal
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Location: Paris, FR
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BLAKE2b (challenge) = 5e082983f7b07fefeff1303209caeb9eccaa1ccd5ec365d09cdcb413b9f9fecfd85f79c577028e67efd9ff1f062c8b603b65a6e5ed51b98bd477704a1341034d
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BLAKE2b (response) = b39c2f54485df51cd0434b0d3cbfcff7b7cc02c2e941097526cf5e605c9f8aaddd3cf9372d0e567cad8c49d7b507a47dac7510203a7f2f00b7d7810636064f06
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https://github.com/LeBleu89/powersoftau-tools/
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- - Binaries and packages used to create response file
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- - Some pictures
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Preparation steps
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=================
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Git repository: https://github.com/ebfull/powersoftau
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Commit hash: d47a1d3d1f007063cbcc35f1ab902601a8b3bd91
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powersoftau-master-d47a1d3.zip : SHA256 = 0902301defc0705d3d824d9ec17382f40785cb9ce84502ee13b774840752def7
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rust-1.21.0-1.fc27.x86_64.rpm : SHA256 = c4abe782505c90232fa65eb6f3de550cf3068cc3f4ba8dfeeb3a4967fc783aea
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cargo-0.22.0-1.fc27.x86_64.rpm : SHA256 = 078b1292716488af6b96494a581726565c24e41b913a424b7a2fbfdf73ccb613
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Fedora-Workstation-Live-x86_64-27-1.6.iso : SHA256 = d242345fa6b5f8cc80e2317c46d15bb1fc4ad70b9a3516c9bc2fb6f3599c8117
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I burned 3 DVD-R with all needed software :
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1) Fedora 27 Live DVD
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2) compute binary (build by myself) and brasero software
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3) challenge file
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Sidechannel Defences
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====================
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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.
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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.
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All the computing process was done on RAM and i run 1 pass of Memtest before and 2 passes after.
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I was alone in my flat(except my cat) during the compute process with no device around the compute node.
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Procedure
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=========
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I downloaded Fedora iso and challenge file on my daily computer and i burned then into DVD-R media.
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I booted the airgap compute node, on Fedora Live DVD and I created a ramfs partition to store compute binary and challenge file.
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I enter some text to provide additional entropy as requested :
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- - License plate of random cars in the street
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- - Words taken randomly in one book on my desk
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- - Random type on keyboard
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Computing process took around 1 hour.
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I burned a 4th DVD-R with response file and I inserted it inside my daily computer to upload it.
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The BLAKE2b hash of `./response` is:
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b39c2f54 485df51c d0434b0d 3cbfcff7
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b7cc02c2 e9410975 26cf5e60 5c9f8aad
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dd3cf937 2d0e567c ad8c49d7 b507a47d
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ac751020 3a7f2f00 b7d78106 36064f06
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Postprocessing
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==============
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I destroyed the 4 DVD and i run a complete Memtest on compute node, 2 passes.
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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.
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- ---
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Fabrice MARCHAL
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