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Powers of Tau Operational writeup
=================================
Round: 1
Date: 2011-11-10
Name: Andrew Miller
Location: Champaign, Illinois

Challenge: (genesis)
ce00f2100dd876fdff8dd824f55307bcb72d724f29ff20b9e0760f3a65e5588a65eaed57cbc61697111ae1f4cc7da2e62a85311c2ae683a041fb872b891c68dc
Response:
15729e0edc4201dc5ee6241437d926f614cb4214ff1b9c6fbd73daf401639f7a4238cf04bc94edac9f2ad037003daab9a4408ba7c62a4413dc2a0ddd683bd719
./response-2017-11-10-amiller

Preparation steps
=================
I used Sean’s powersoftau rust repo, commit
9e1553c437183540392a7231d0788318a19b18a3

I followed instructions online for building portable rust binaries,
and so I ran
```
cargo build --target=x86_64-unknown-linux-musl --release --features=u128-support --bin=compute
```

Compiler: rustc 1.23.0-nightly (02004ef78 2017-11-08)

I copied the resulting binary to a freshly formatted USB stick I had.

b2sum:
9059a0a64f5021c36df630ca48ac40674862b2fea14f4843ff2150256b95162ac4d6d1621d2dd3f5d0d1c604ad8e581c0ff449d2449140380eab075a9b83c960
./target/x86_64-unknown-linux-musl/release/compute

I also rummaged through my shelf of several USB sticks, and found one
that happened to be a Linux Mint 18 USB bootable disk, so I used that
for my operating system.

Sidechannel defenses
====================
I used an airgap compute node, a Dell Inspiron that I’ve had for about
a year now (Actually this is a computer I bought last year for
dress-rehearsals in the Zcash Sprout param generation ceremony).

I unplugged all the computer’s hard drives, and detached its
wifi/bluetooth radios. I booted the computer from the Linux Mint
livecd usb stick, and then also copied the binaries into RAM. The
compute node was located in my bedroom, and I attended it for the ~1hr
duration of the compute process.

Image: https://pbs.twimg.com/media/DOSZz4FXkAEKC7N.jpg:large

Postprocessing
==============
After compute was finished, I took a cell phone picture of the blake2b
hash of the response. I then copied the response file to the USB stick
containing the binaries, and then I unplugged the compute node. Using
my personal laptop, I posted the blake2b hash to the #mpc chat and
uploaded the response file to s3. 

The repsonse file is hosted here for now, though I expect we'll
mirror it elsewhere later:
https://s3.amazonaws.com/socrates1024_a/response-2017-11-10-amiller

I did not destroy the compute node and do plan to use it again,
although I'm going to leave it unplugged for several days.
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