76 lines
3.0 KiB
Plaintext
76 lines
3.0 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: 3
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Date: 2017-11-12
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Name: Jared Tobin
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Location: Auckland, NZ
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Challenge:
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e712fa22f1d027a0b4ce3ef698f26d5cab07c3380e4c24a479a914c85617fd1a2960b386cceb5c94718979010a1b7ed8b6145da872f0744e06503bd664fe7283
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Response:
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cb48afb82ab4c476ae741633c3eb6643e7700dc7b2b4701af91e3cc932270b96c375e5f3a5c20c96fac6c9b40a5bba6c956d66f223f090c545c277aa05427757
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Preparation Steps
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=================
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Being somewhat pressed for time and hardware, I recruited several
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geographically-distributed volunteers that I know well and trust
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completely to help me out. In the end, the following volunteers were
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able to get back to me in time:
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* Shawn Tobin (RSA Canada)
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* Fredrik Harryson (Parity Technologies)
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* Jason Forbes (Kraken Sonar Systems)
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I set up a private Keybase team with the above volunteers, distributed
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the challenge to them over KBFS, and gave them instructions over the
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team chat on how to proceed. Each was to add entropy and compute the
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response locally using whatever mechanisms they preferred (report not
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required), then return their response/hash pairs to me over KBFS. Each
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member was to use the code in Sean's powersoftau repository as of commit
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9e1553c437183540392a7231d0788318a19b18a3 to perform the computation.
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Procedure
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=========
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I computed a response locally in rather mundane fashion using rustc
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1.21.0 on an early-2015 model Macbook Air running Sierra. Eventually
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the volunteers managed to upload their response/hash pairs to KBFS, and
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I randomly selected one of the resulting four responses to submit for my
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piece of the MPC.
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I uploaded the resulting response via the handy app Sean provided me with.
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Side channel defences
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=====================
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I used broad geographical distribution and randomness to mitigate the
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possibility of successful side channel attacks. Shawn was located in
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Vancouver, Canada, Fredrik was located in Malmö, Sweden, and Jason was
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located in St. John's, Canada.
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I selected the response to upload by pre-determining a correspondence
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between names and numbers, and then walking outside and asking the first
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stranger I saw to pick a number between one and four.
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