Frances He Franceshe

Arweave GraphQL Guide

Retrieving Data

In order to retrieve data from Arweave, you can use the following example query to retrieve the entire transaction output.

query {
    transactions {
        cursor

Design for a CoinSwap Implementation for Massively Improving Bitcoin Privacy and Fungibility

25/5/2020

Abstract

Imagine a future where a user Alice has bitcoins and wants to send them with maximal privacy, so she creates a special kind of transaction. For anyone looking at the blockchain her transaction appears completely normal with her coins seemingly going from address A to address B. But in reality her coins end up in address Z which is entirely unconnected to either A or B.

Now imagine another user, Carol, who isn't too bothered by privacy and sends her bitcoin using a regular wallet which exists today. But because Carol's transaction looks exactly the same as Alice's, anybody analyzing the blockchain must now deal with the possibility that Carol's transaction actually sent her coins to a totally unconnected address. So Carol's privacy is improved even though she didn't change her behaviour, and perhaps had never even heard of this software.

Feel free to copy and paste this list into a README, issue or elsewhere in your project.

Audit prep checklist (reference)

Documentation (A plain english description of what you are building, and why you are building it. Should indicate the actions and states that should and should not be possible)
- For the overall system
- For each unique contract within the system
Clean code
- Run a linter (like EthLint)
Fix compiler warnings

Diagrams

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Please note that some diagrams don't work well with file exports such as PDF, pandoc, etc.

Flow Charts

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From an open Jupyter Notebook homework assignment, select "Coursera" to take you to the home page. Make a new notebook and fill it with the following and excute the cell with:

%%bash
tar cvfz hw.tar.gz .

This may take a little while to run depending on the packages. Select "Coursera" again to take you to the Home directory. Check the hw.tar.gz file and then Download. After the file is downloaded, delete it.

	// SPDX-License-Identifier: MIT
	pragma solidity ^0.8.4;

	import "@openzeppelin/[email protected]/token/ERC20/ERC20.sol";
	import "@openzeppelin/[email protected]/token/ERC721/IERC721.sol";
	import "@openzeppelin/[email protected]/access/Ownable.sol";
	import "@openzeppelin/[email protected]/token/ERC20/extensions/draft-ERC20Permit.sol";
	import "@openzeppelin/[email protected]/token/ERC721/utils/ERC721Holder.sol";

	contract FractionalizedNFT is ERC20, Ownable, ERC20Permit, ERC721Holder {

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	cd

	git clone --depth=1 --single-branch \
	--branch emacs-27 https://github.com/emacs-mirror/emacs.git

	cd emacs/

	sudo apt install -y autoconf make gcc texinfo libgtk-3-dev libxpm-dev \
	libjpeg-dev libgif-dev libtiff5-dev libgnutls28-dev libncurses5-dev \
	libjansson-dev libharfbuzz-dev libharfbuzz-bin imagemagick \

	// SPDX-License-Identifier: AGPL-3.0-or-later

	// The ABI encoder is necessary, but older Solidity versions should work
	pragma solidity ^0.7.0;
	pragma experimental ABIEncoderV2;

	// These definitions are taken from across multiple dydx contracts, and are
	// limited to just the bare minimum necessary to make flash loans work.
	library Types {
	enum AssetDenomination { Wei, Par }

	(ns doubanbook-cralwer.core
	(:require [clj-http.client :as http]
	[clojure.core.async :refer [go-loop chan <! >!! <!!] :as a]
	[taoensso.carmine :as car :refer (wcar)])
	(:gen-class))

	(def ua "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.122 Safari/537.36")
	(def redis-opts {:pool {} :spec {:uri "redis://127.0.0.1:6379/0"}})
	(defmacro wcar* [& body] `(car/wcar redis-opts ~@body))
	(def seen (atom (into #{} (wcar* (car/keys "*")))))