60 skills found · Page 1 of 2
cheat-engine / Cheat EngineCheat Engine. A development environment focused on modding
logeshpaul / Frontend Cheat SheetsCollection of cheat sheets(HTML, CSS, JS, Git, Gulp, etc.,) for your frontend development needs & reference
WebdevShefali / CheatSheetsA collection of high-quality cheat sheets for web development technologies, including CSS, Git, HTML, and VSCode.
WebdevShefali / Web Dev ResourcesA collection of free web development resources, including APIs, hosting platforms, cheat sheets, icons, templates, fonts, color tools, learning platforms, and more. 🚀
cs1ime / Blacksun Frameworkblacksun framework for QEMU/KVM game cheat development
degeneratehyperbola / NEPSBloat-free CS:GO multihack for Windows, based on Osiris. You should probably give it a go, as it was in development for about 2 years. Formerly a griefing cheat that developed into a semi-rage multihack, with many features added, bugs fixed, things optimized and more!
orange-cpp / OmathCross-platform modern general purpose game/mods/cheats development framework written in C++23.
Temidtech / Dart Cheat SheetA curated list of awesome cheats needed to quickly get started with flutter development.
averagesecurityguy / Cheat SheetsVarious Cheat Sheets related to development and security
JeffDeCola / My Cheat SheetsA place to keep all my cheat sheets for the complete development of ASIC/FPGA hardware or a software app/service.
Blockception / VSCode Bedrock Development ExtensionAn extension that provides support for files such as: .mcfunction, .json and .lang. Features include: completion, validations, formatters, diagnostics, cheat-sheets, code-actions, generation of files, and development tools to help develop Minecraft Bedrock Addons or Minecraft Education Edition.
groupe-sii / Cheat SheetsA collection of cheat sheets usefull for web development
rramatchandran / Big O Performance Java# big-o-performance A simple html app to demonstrate performance costs of data structures. - Clone the project - Navigate to the root of the project in a termina or command prompt - Run 'npm install' - Run 'npm start' - Go to the URL specified in the terminal or command prompt to try out the app. # This app was created from the Create React App NPM. Below are instructions from that project. Below you will find some information on how to perform common tasks. You can find the most recent version of this guide [here](https://github.com/facebookincubator/create-react-app/blob/master/template/README.md). ## Table of Contents - [Updating to New Releases](#updating-to-new-releases) - [Sending Feedback](#sending-feedback) - [Folder Structure](#folder-structure) - [Available Scripts](#available-scripts) - [npm start](#npm-start) - [npm run build](#npm-run-build) - [npm run eject](#npm-run-eject) - [Displaying Lint Output in the Editor](#displaying-lint-output-in-the-editor) - [Installing a Dependency](#installing-a-dependency) - [Importing a Component](#importing-a-component) - [Adding a Stylesheet](#adding-a-stylesheet) - [Post-Processing CSS](#post-processing-css) - [Adding Images and Fonts](#adding-images-and-fonts) - [Adding Bootstrap](#adding-bootstrap) - [Adding Flow](#adding-flow) - [Adding Custom Environment Variables](#adding-custom-environment-variables) - [Integrating with a Node Backend](#integrating-with-a-node-backend) - [Proxying API Requests in Development](#proxying-api-requests-in-development) - [Deployment](#deployment) - [Now](#now) - [Heroku](#heroku) - [Surge](#surge) - [GitHub Pages](#github-pages) - [Something Missing?](#something-missing) ## Updating to New Releases Create React App is divided into two packages: * `create-react-app` is a global command-line utility that you use to create new projects. * `react-scripts` is a development dependency in the generated projects (including this one). You almost never need to update `create-react-app` itself: it’s delegates all the setup to `react-scripts`. When you run `create-react-app`, it always creates the project with the latest version of `react-scripts` so you’ll get all the new features and improvements in newly created apps automatically. To update an existing project to a new version of `react-scripts`, [open the changelog](https://github.com/facebookincubator/create-react-app/blob/master/CHANGELOG.md), find the version you’re currently on (check `package.json` in this folder if you’re not sure), and apply the migration instructions for the newer versions. In most cases bumping the `react-scripts` version in `package.json` and running `npm install` in this folder should be enough, but it’s good to consult the [changelog](https://github.com/facebookincubator/create-react-app/blob/master/CHANGELOG.md) for potential breaking changes. We commit to keeping the breaking changes minimal so you can upgrade `react-scripts` painlessly. ## Sending Feedback We are always open to [your feedback](https://github.com/facebookincubator/create-react-app/issues). ## Folder Structure After creation, your project should look like this: ``` my-app/ README.md index.html favicon.ico node_modules/ package.json src/ App.css App.js index.css index.js logo.svg ``` For the project to build, **these files must exist with exact filenames**: * `index.html` is the page template; * `favicon.ico` is the icon you see in the browser tab; * `src/index.js` is the JavaScript entry point. You can delete or rename the other files. You may create subdirectories inside `src`. For faster rebuilds, only files inside `src` are processed by Webpack. You need to **put any JS and CSS files inside `src`**, or Webpack won’t see them. You can, however, create more top-level directories. They will not be included in the production build so you can use them for things like documentation. ## Available Scripts In the project directory, you can run: ### `npm start` Runs the app in the development mode.<br> Open [http://localhost:3000](http://localhost:3000) to view it in the browser. The page will reload if you make edits.<br> You will also see any lint errors in the console. ### `npm run build` Builds the app for production to the `build` folder.<br> It correctly bundles React in production mode and optimizes the build for the best performance. The build is minified and the filenames include the hashes.<br> Your app is ready to be deployed! ### `npm run eject` **Note: this is a one-way operation. Once you `eject`, you can’t go back!** If you aren’t satisfied with the build tool and configuration choices, you can `eject` at any time. This command will remove the single build dependency from your project. Instead, it will copy all the configuration files and the transitive dependencies (Webpack, Babel, ESLint, etc) right into your project so you have full control over them. All of the commands except `eject` will still work, but they will point to the copied scripts so you can tweak them. At this point you’re on your own. You don’t have to ever use `eject`. The curated feature set is suitable for small and middle deployments, and you shouldn’t feel obligated to use this feature. However we understand that this tool wouldn’t be useful if you couldn’t customize it when you are ready for it. ## Displaying Lint Output in the Editor >Note: this feature is available with `react-scripts@0.2.0` and higher. Some editors, including Sublime Text, Atom, and Visual Studio Code, provide plugins for ESLint. They are not required for linting. You should see the linter output right in your terminal as well as the browser console. However, if you prefer the lint results to appear right in your editor, there are some extra steps you can do. You would need to install an ESLint plugin for your editor first. >**A note for Atom `linter-eslint` users** >If you are using the Atom `linter-eslint` plugin, make sure that **Use global ESLint installation** option is checked: ><img src="http://i.imgur.com/yVNNHJM.png" width="300"> Then make sure `package.json` of your project ends with this block: ```js { // ... "eslintConfig": { "extends": "./node_modules/react-scripts/config/eslint.js" } } ``` Projects generated with `react-scripts@0.2.0` and higher should already have it. If you don’t need ESLint integration with your editor, you can safely delete those three lines from your `package.json`. Finally, you will need to install some packages *globally*: ```sh npm install -g eslint babel-eslint eslint-plugin-react eslint-plugin-import eslint-plugin-jsx-a11y eslint-plugin-flowtype ``` We recognize that this is suboptimal, but it is currently required due to the way we hide the ESLint dependency. The ESLint team is already [working on a solution to this](https://github.com/eslint/eslint/issues/3458) so this may become unnecessary in a couple of months. ## Installing a Dependency The generated project includes React and ReactDOM as dependencies. It also includes a set of scripts used by Create React App as a development dependency. You may install other dependencies (for example, React Router) with `npm`: ``` npm install --save <library-name> ``` ## Importing a Component This project setup supports ES6 modules thanks to Babel. While you can still use `require()` and `module.exports`, we encourage you to use [`import` and `export`](http://exploringjs.com/es6/ch_modules.html) instead. For example: ### `Button.js` ```js import React, { Component } from 'react'; class Button extends Component { render() { // ... } } export default Button; // Don’t forget to use export default! ``` ### `DangerButton.js` ```js import React, { Component } from 'react'; import Button from './Button'; // Import a component from another file class DangerButton extends Component { render() { return <Button color="red" />; } } export default DangerButton; ``` Be aware of the [difference between default and named exports](http://stackoverflow.com/questions/36795819/react-native-es-6-when-should-i-use-curly-braces-for-import/36796281#36796281). It is a common source of mistakes. We suggest that you stick to using default imports and exports when a module only exports a single thing (for example, a component). That’s what you get when you use `export default Button` and `import Button from './Button'`. Named exports are useful for utility modules that export several functions. A module may have at most one default export and as many named exports as you like. Learn more about ES6 modules: * [When to use the curly braces?](http://stackoverflow.com/questions/36795819/react-native-es-6-when-should-i-use-curly-braces-for-import/36796281#36796281) * [Exploring ES6: Modules](http://exploringjs.com/es6/ch_modules.html) * [Understanding ES6: Modules](https://leanpub.com/understandinges6/read#leanpub-auto-encapsulating-code-with-modules) ## Adding a Stylesheet This project setup uses [Webpack](https://webpack.github.io/) for handling all assets. Webpack offers a custom way of “extending” the concept of `import` beyond JavaScript. To express that a JavaScript file depends on a CSS file, you need to **import the CSS from the JavaScript file**: ### `Button.css` ```css .Button { padding: 20px; } ``` ### `Button.js` ```js import React, { Component } from 'react'; import './Button.css'; // Tell Webpack that Button.js uses these styles class Button extends Component { render() { // You can use them as regular CSS styles return <div className="Button" />; } } ``` **This is not required for React** but many people find this feature convenient. You can read about the benefits of this approach [here](https://medium.com/seek-ui-engineering/block-element-modifying-your-javascript-components-d7f99fcab52b). However you should be aware that this makes your code less portable to other build tools and environments than Webpack. In development, expressing dependencies this way allows your styles to be reloaded on the fly as you edit them. In production, all CSS files will be concatenated into a single minified `.css` file in the build output. If you are concerned about using Webpack-specific semantics, you can put all your CSS right into `src/index.css`. It would still be imported from `src/index.js`, but you could always remove that import if you later migrate to a different build tool. ## Post-Processing CSS This project setup minifies your CSS and adds vendor prefixes to it automatically through [Autoprefixer](https://github.com/postcss/autoprefixer) so you don’t need to worry about it. For example, this: ```css .App { display: flex; flex-direction: row; align-items: center; } ``` becomes this: ```css .App { display: -webkit-box; display: -ms-flexbox; display: flex; -webkit-box-orient: horizontal; -webkit-box-direction: normal; -ms-flex-direction: row; flex-direction: row; -webkit-box-align: center; -ms-flex-align: center; align-items: center; } ``` There is currently no support for preprocessors such as Less, or for sharing variables across CSS files. ## Adding Images and Fonts With Webpack, using static assets like images and fonts works similarly to CSS. You can **`import` an image right in a JavaScript module**. This tells Webpack to include that image in the bundle. Unlike CSS imports, importing an image or a font gives you a string value. This value is the final image path you can reference in your code. Here is an example: ```js import React from 'react'; import logo from './logo.png'; // Tell Webpack this JS file uses this image console.log(logo); // /logo.84287d09.png function Header() { // Import result is the URL of your image return <img src={logo} alt="Logo" />; } export default function Header; ``` This works in CSS too: ```css .Logo { background-image: url(./logo.png); } ``` Webpack finds all relative module references in CSS (they start with `./`) and replaces them with the final paths from the compiled bundle. If you make a typo or accidentally delete an important file, you will see a compilation error, just like when you import a non-existent JavaScript module. The final filenames in the compiled bundle are generated by Webpack from content hashes. If the file content changes in the future, Webpack will give it a different name in production so you don’t need to worry about long-term caching of assets. Please be advised that this is also a custom feature of Webpack. **It is not required for React** but many people enjoy it (and React Native uses a similar mechanism for images). However it may not be portable to some other environments, such as Node.js and Browserify. If you prefer to reference static assets in a more traditional way outside the module system, please let us know [in this issue](https://github.com/facebookincubator/create-react-app/issues/28), and we will consider support for this. ## Adding Bootstrap You don’t have to use [React Bootstrap](https://react-bootstrap.github.io) together with React but it is a popular library for integrating Bootstrap with React apps. If you need it, you can integrate it with Create React App by following these steps: Install React Bootstrap and Bootstrap from NPM. React Bootstrap does not include Bootstrap CSS so this needs to be installed as well: ``` npm install react-bootstrap --save npm install bootstrap@3 --save ``` Import Bootstrap CSS and optionally Bootstrap theme CSS in the ```src/index.js``` file: ```js import 'bootstrap/dist/css/bootstrap.css'; import 'bootstrap/dist/css/bootstrap-theme.css'; ``` Import required React Bootstrap components within ```src/App.js``` file or your custom component files: ```js import { Navbar, Jumbotron, Button } from 'react-bootstrap'; ``` Now you are ready to use the imported React Bootstrap components within your component hierarchy defined in the render method. Here is an example [`App.js`](https://gist.githubusercontent.com/gaearon/85d8c067f6af1e56277c82d19fd4da7b/raw/6158dd991b67284e9fc8d70b9d973efe87659d72/App.js) redone using React Bootstrap. ## Adding Flow Flow typing is currently [not supported out of the box](https://github.com/facebookincubator/create-react-app/issues/72) with the default `.flowconfig` generated by Flow. If you run it, you might get errors like this: ```js node_modules/fbjs/lib/Deferred.js.flow:60 60: Promise.prototype.done.apply(this._promise, arguments); ^^^^ property `done`. Property not found in 495: declare class Promise<+R> { ^ Promise. See lib: /private/tmp/flow/flowlib_34952d31/core.js:495 node_modules/fbjs/lib/shallowEqual.js.flow:29 29: return x !== 0 || 1 / (x: $FlowIssue) === 1 / (y: $FlowIssue); ^^^^^^^^^^ identifier `$FlowIssue`. Could not resolve name src/App.js:3 3: import logo from './logo.svg'; ^^^^^^^^^^^^ ./logo.svg. Required module not found src/App.js:4 4: import './App.css'; ^^^^^^^^^^^ ./App.css. Required module not found src/index.js:5 5: import './index.css'; ^^^^^^^^^^^^^ ./index.css. Required module not found ``` To fix this, change your `.flowconfig` to look like this: ```ini [libs] ./node_modules/fbjs/flow/lib [options] esproposal.class_static_fields=enable esproposal.class_instance_fields=enable module.name_mapper='^\(.*\)\.css$' -> 'react-scripts/config/flow/css' module.name_mapper='^\(.*\)\.\(jpg\|png\|gif\|eot\|otf\|webp\|svg\|ttf\|woff\|woff2\|mp4\|webm\)$' -> 'react-scripts/config/flow/file' suppress_type=$FlowIssue suppress_type=$FlowFixMe ``` Re-run flow, and you shouldn’t get any extra issues. If you later `eject`, you’ll need to replace `react-scripts` references with the `<PROJECT_ROOT>` placeholder, for example: ```ini module.name_mapper='^\(.*\)\.css$' -> '<PROJECT_ROOT>/config/flow/css' module.name_mapper='^\(.*\)\.\(jpg\|png\|gif\|eot\|otf\|webp\|svg\|ttf\|woff\|woff2\|mp4\|webm\)$' -> '<PROJECT_ROOT>/config/flow/file' ``` We will consider integrating more tightly with Flow in the future so that you don’t have to do this. ## Adding Custom Environment Variables >Note: this feature is available with `react-scripts@0.2.3` and higher. Your project can consume variables declared in your environment as if they were declared locally in your JS files. By default you will have `NODE_ENV` defined for you, and any other environment variables starting with `REACT_APP_`. These environment variables will be defined for you on `process.env`. For example, having an environment variable named `REACT_APP_SECRET_CODE` will be exposed in your JS as `process.env.REACT_APP_SECRET_CODE`, in addition to `process.env.NODE_ENV`. These environment variables can be useful for displaying information conditionally based on where the project is deployed or consuming sensitive data that lives outside of version control. First, you need to have environment variables defined, which can vary between OSes. For example, let's say you wanted to consume a secret defined in the environment inside a `<form>`: ```jsx render() { return ( <div> <small>You are running this application in <b>{process.env.NODE_ENV}</b> mode.</small> <form> <input type="hidden" defaultValue={process.env.REACT_APP_SECRET_CODE} /> </form> </div> ); } ``` The above form is looking for a variable called `REACT_APP_SECRET_CODE` from the environment. In order to consume this value, we need to have it defined in the environment: ### Windows (cmd.exe) ```cmd set REACT_APP_SECRET_CODE=abcdef&&npm start ``` (Note: the lack of whitespace is intentional.) ### Linux, OS X (Bash) ```bash REACT_APP_SECRET_CODE=abcdef npm start ``` > Note: Defining environment variables in this manner is temporary for the life of the shell session. Setting permanent environment variables is outside the scope of these docs. With our environment variable defined, we start the app and consume the values. Remember that the `NODE_ENV` variable will be set for you automatically. When you load the app in the browser and inspect the `<input>`, you will see its value set to `abcdef`, and the bold text will show the environment provided when using `npm start`: ```html <div> <small>You are running this application in <b>development</b> mode.</small> <form> <input type="hidden" value="abcdef" /> </form> </div> ``` Having access to the `NODE_ENV` is also useful for performing actions conditionally: ```js if (process.env.NODE_ENV !== 'production') { analytics.disable(); } ``` ## Integrating with a Node Backend Check out [this tutorial](https://www.fullstackreact.com/articles/using-create-react-app-with-a-server/) for instructions on integrating an app with a Node backend running on another port, and using `fetch()` to access it. You can find the companion GitHub repository [here](https://github.com/fullstackreact/food-lookup-demo). ## Proxying API Requests in Development >Note: this feature is available with `react-scripts@0.2.3` and higher. People often serve the front-end React app from the same host and port as their backend implementation. For example, a production setup might look like this after the app is deployed: ``` / - static server returns index.html with React app /todos - static server returns index.html with React app /api/todos - server handles any /api/* requests using the backend implementation ``` Such setup is **not** required. However, if you **do** have a setup like this, it is convenient to write requests like `fetch('/api/todos')` without worrying about redirecting them to another host or port during development. To tell the development server to proxy any unknown requests to your API server in development, add a `proxy` field to your `package.json`, for example: ```js "proxy": "http://localhost:4000", ``` This way, when you `fetch('/api/todos')` in development, the development server will recognize that it’s not a static asset, and will proxy your request to `http://localhost:4000/api/todos` as a fallback. Conveniently, this avoids [CORS issues](http://stackoverflow.com/questions/21854516/understanding-ajax-cors-and-security-considerations) and error messages like this in development: ``` Fetch API cannot load http://localhost:4000/api/todos. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled. ``` Keep in mind that `proxy` only has effect in development (with `npm start`), and it is up to you to ensure that URLs like `/api/todos` point to the right thing in production. You don’t have to use the `/api` prefix. Any unrecognized request will be redirected to the specified `proxy`. Currently the `proxy` option only handles HTTP requests, and it won’t proxy WebSocket connections. If the `proxy` option is **not** flexible enough for you, alternatively you can: * Enable CORS on your server ([here’s how to do it for Express](http://enable-cors.org/server_expressjs.html)). * Use [environment variables](#adding-custom-environment-variables) to inject the right server host and port into your app. ## Deployment By default, Create React App produces a build assuming your app is hosted at the server root. To override this, specify the `homepage` in your `package.json`, for example: ```js "homepage": "http://mywebsite.com/relativepath", ``` This will let Create React App correctly infer the root path to use in the generated HTML file. ### Now See [this example](https://github.com/xkawi/create-react-app-now) for a zero-configuration single-command deployment with [now](https://zeit.co/now). ### Heroku Use the [Heroku Buildpack for Create React App](https://github.com/mars/create-react-app-buildpack). You can find instructions in [Deploying React with Zero Configuration](https://blog.heroku.com/deploying-react-with-zero-configuration). ### Surge Install the Surge CLI if you haven't already by running `npm install -g surge`. Run the `surge` command and log in you or create a new account. You just need to specify the *build* folder and your custom domain, and you are done. ```sh email: email@domain.com password: ******** project path: /path/to/project/build size: 7 files, 1.8 MB domain: create-react-app.surge.sh upload: [====================] 100%, eta: 0.0s propagate on CDN: [====================] 100% plan: Free users: email@domain.com IP Address: X.X.X.X Success! Project is published and running at create-react-app.surge.sh ``` Note that in order to support routers that use html5 `pushState` API, you may want to rename the `index.html` in your build folder to `200.html` before deploying to Surge. This [ensures that every URL falls back to that file](https://surge.sh/help/adding-a-200-page-for-client-side-routing). ### GitHub Pages >Note: this feature is available with `react-scripts@0.2.0` and higher. Open your `package.json` and add a `homepage` field: ```js "homepage": "http://myusername.github.io/my-app", ``` **The above step is important!** Create React App uses the `homepage` field to determine the root URL in the built HTML file. Now, whenever you run `npm run build`, you will see a cheat sheet with a sequence of commands to deploy to GitHub pages: ```sh git commit -am "Save local changes" git checkout -B gh-pages git add -f build git commit -am "Rebuild website" git filter-branch -f --prune-empty --subdirectory-filter build git push -f origin gh-pages git checkout - ``` You may copy and paste them, or put them into a custom shell script. You may also customize them for another hosting provider. Note that GitHub Pages doesn't support routers that use the HTML5 `pushState` history API under the hood (for example, React Router using `browserHistory`). This is because when there is a fresh page load for a url like `http://user.github.io/todomvc/todos/42`, where `/todos/42` is a frontend route, the GitHub Pages server returns 404 because it knows nothing of `/todos/42`. If you want to add a router to a project hosted on GitHub Pages, here are a couple of solutions: * You could switch from using HTML5 history API to routing with hashes. If you use React Router, you can switch to `hashHistory` for this effect, but the URL will be longer and more verbose (for example, `http://user.github.io/todomvc/#/todos/42?_k=yknaj`). [Read more](https://github.com/reactjs/react-router/blob/master/docs/guides/Histories.md#histories) about different history implementations in React Router. * Alternatively, you can use a trick to teach GitHub Pages to handle 404 by redirecting to your `index.html` page with a special redirect parameter. You would need to add a `404.html` file with the redirection code to the `build` folder before deploying your project, and you’ll need to add code handling the redirect parameter to `index.html`. You can find a detailed explanation of this technique [in this guide](https://github.com/rafrex/spa-github-pages). ## Something Missing? If you have ideas for more “How To” recipes that should be on this page, [let us know](https://github.com/facebookincubator/create-react-app/issues) or [contribute some!](https://github.com/facebookincubator/create-react-app/edit/master/template/README.md)
Yoloyoda / Abap For Cloud Development CheatsheetCheatsheet for smooth adaptation to ABAP on Cloud
rmccrystal / Memlib RsA cross platform memory hacking library written in Rust aimed at cheat development.
ridpath / Gamehacking CheatsheetComprehensive Game Hacking Cheat Sheet for security researchers, reverse engineers, and CTF participants. Covers memory analysis, anti-cheat evasion, exploit development, and game engine reverse engineering for authorized security testing and educational purposes
acumino / Cheat SheetsThis repository is a centralized collection of cheat sheets for various tools and technologies commonly used in software development, system administration, and infrastructure management.
Ritika-Agrawal811 / SheetDeckA collection of web development cheat sheets and visuals I’ve put together!
BlockchainLabs / SpreadCoinSpreadCoin October 5, 2014 Introduction In proof-of-work cryptocurrencies new coins are generated by the network through the process of mining. One of the purposes of mining is to protect network from double spending attacks and history rewriting. Miners generate new blocks and check contents of the blocks generated by other peers for conformation to the network rules. However, many miners now delegate all the checking work crucial to cryptocurrency security to pools. This means that pool operators do not have any large hashing power but have control over generation of new blocks. This brings unnecessary centralization to otherwise decentralized system. Controlling more than 50% of mining power allows to perform double-spending attacks with 100% chance of success but even with less than 50% control it is possible to perform attacks which have chances to succeed1 . The core idea of SpreadCoin is to prevent creation of pools and thus make mining more decentralized and the whole system more secure. Pool Prevention In pooled mining miners perform only the work which is necessary to fulfill the proof-of-work requirements and pools take care of block generation and broadcasting and distribute reward among miners according to the shares they submit. In this scheme miner has two alternatives: 1. Solo mining. In this case miner cannot send shares to the pool because they will not be accepted. 2. Pooled mining. Miner’s shares will be accepted by the pool but in the case miner will actually generate a new block its reward will go to the pool which will redistribute it to all miners. This allows organization of pools because miners has no way to cheat and steal generated money. To prevent creation of pools we must remove this possibility so that if pool will be created than miner can mine in a pool, submit shares as usual and get reward for them but in the case of actually finding a block miner can send it directly to the network instead of the pool and get full reward for it. In SpreadCoin mining is organized in such way that miner must know the following things: 1. Private key corresponding to the coinbase transaction. 2. Whole block, not only its header. This ensures that miner can broadcast mined block and spend coins generated in that block. It may seem that it is necessary to know only the private key to spend coinbase transaction. If two conflicting transactions will appear on the network then the one that was broadcasted first will have much higher probability to be included in a block because each peer remembers and retransmits only the first one of the conflicting transactions. If both miner and pool know private key but only pool knows the content of the block than pool can generate and broadcast spending transaction earlier than miner. If both miner 1 Double-spending. Bitcoin Wiki. https://en.bitcoin.it/wiki/Double-spending and pool know content of the block than miner will be the first one who can broadcast block and spending transaction. To prove knowledge of the private key and whole block there are two new fields in the block header: MinerSignature and hashWholeBlock. MinerSignature is a digital signature of all fields of the block header except for the hashWholeBlock. Changing any information in the block requires regeneration of this signature which means that it is necessary to recalculate it during each iteration of the mining process. This implies that miner must be able to sign any arbitrary data. hashWholeBlock is a SHA-256 hash of the block data arranged as follows: Padding ensures that there is no incentive to mine empty blocks without transactions. Padding values are computed using simple algorithm which initializes last 32 bytes (8 uint32) with hashPrevBlock and then goes backward and computes remaining uint32 values using the following recursive formula: 𝐼𝑖 = 𝐼𝑖+3 ∙ 𝐼𝑖+7. This algorithm ensures that there is no efficient way to compute padding values on the fly during hash computation which otherwise could potentially give some advantage to mine empty blocks in certain computing environments. It is important that block is hashed twice. If it was hashed only once then pool could hash the beginning of the block and send resulting hash state to the miners. Each miner would then modify some information in the end of the block and recalculate the hash based on the known state without actual knowledge about what is contained in the beginning of the block. Appending block data to itself make it necessary to know the whole block to recalculate hashWholeBlock. Pool may detect and ban cheating miners. However, many miners may still prefer to cheat so that pool will be completely unusable for honest miners. Miners that have low probability of finding a block will get more profit by stealing reward for accidentally found block even if pool will ban them thereafter. Miners that have enough mining power to find blocks consistently can still connect to a pool and submit shares for some time but steal the first found block. This way they can get both reward for their shares and the actual mined block. Given all this it is expected that no one will create a pool. But even if someone will than it can be countered by releasing stealing miner software which many miners will switch to. Compact Transactions SpreadCoin as well as Bitcoin uses ECDSA signatures. Each address in Bitcoin is a hash of an ECDSA public key. To spend coins sent to an address it is necessary to provide public key matching to that hash and a signature. This results in 139 or 107 bytes for each transaction input script (scriptSig) depending on Block Padding MAX_BLOCK_SIZE Block Padding whether compact public key is used. However, it is possible to recover public key from the signature2 which means that it is not necessary to provide it in transaction input. Together with using compact representation of the signature3 it allows to reduce size of transaction input script from 139 or 107 bytes in Bitcoin to 67 bytes in SpreadCoin. Recovering public key has almost no extra CPU cost compared to the usual signature verification process used in Bitcoin. This is important because the CPU cost of ECDSA signature verification is a bottleneck for Bitcoin transaction processing. Usual output script (scriptPubKey) in Bitcoin looks as follows: OP_DUP OP_HASH160 5bd18804e4bb43a4bb8b6bc88408970bafaf4a38 OP_EQUALVERIFY OP_CHECKSIG In SpreadCoin the semantics of the OP_CHECKSIG instruction was changed to checking signature by hash of the public key (it recovers public key and compares its hash with the provided one). This results in a much simpler script in SpreadCoin: 5bd18804e4bb43a4bb8b6bc88408970bafaf4a38 OP_CHECKSIG This results in additional minor space saving because this script is 3 bytes smaller. Smooth Supply Block reward in Bitcoin is computed using the following formula: 𝑅ℎ = 𝑅0 ∙ 2 −⌊ ℎ 𝑝 ⌋ , where ℎ – block height, 𝑝 – reward halving period, 𝑅0 – initial reward, 𝑅ℎ – reward for block ℎ, ⌊ ⌋ – floor function. This method results in abrupt reward changes near halving points. SpreadCoin uses simple linear interpolation between halving points to make reward decrease much smother. This is achieved by modifying reward using the following formula: 𝑅ℎ ′ = 4 3 (𝑅ℎ − 𝑅ℎ ∙ ℎ mod 𝑝 2𝑝 ). SpreadCoin uses 𝑝 = 2 ∙ 106 as its reward halving period. 2 ECDSA Signatures allow recovery of the public key. Bitcoin Forum. https://bitcointalk.org/?topic=6430.0%29%3F 3 Why the signature is always 65 (1+32+32) bytes long? Bitcoin Stack Exchange. https://bitcoin.stackexchange.com/questions/12554/why-the-signature-is-always-65-13232-bytes-long | NO YEAR 2106 PROBLEM The time stamp field in the block header is now 64 bit instead of 32 bit (Bitcoin) so that much farther date times are possible (>Year 2106) Upcoming features that are in development and will be introduced over the next weeks and months: SERVICENODES A servicenode is a node which runs continuously (24/7) on a server and which provides services within the spreadcoin network. You have to pay a collateral to be able to install a servernode (in return your servicenode will earn a steady income). This collateral is determined by a free market price discovery. (No fix collateral. The price is allowed to fluctuate over time.) COMPETITIVE COLLATERAL Furthermore, to introduce a competitive nature to the servicenodes there will only ever be a limited number of allowed servicenodes worldwide. Since the collateral isn't set in stone, but the amount of servicenodes is fixed, the price of a servicenode will be determined by the participants themselves. It is expected that the price will vary widely over time, which exposes it to the same market forces that hashrate and currency value are exposed to too. SERVICE APPS There are a number of decentralized applications that will run on servicenodes. Most likely those apps will include: 1) "Spread the message" (an in-wallet encrypted messaging system, which allows you to send a message to an SPR address) 2) "Spread the Search" (A decentralized search engine that lets the servicenodes crawl and map the entire internet.) . SPREADX11 SpreadX11 is different from plain X11 by introducing a sophisticated pool prevention mechanism. With SpreadX11 every block header contains additional information (MinerSignature and hashWholeBlock). With the help of this information the protocol ensures that the miner of a new block is always also the first one to know the content of the whole block and the private key to spend the coinbase transaction. (contrary to pool mining where the pool operator is the first one to know those things) So when a miner finds a block, he must himself sign and transmit the block to the network (like solo mining), instead of having a pool handle this for him. This effectively prevents pools by making their rules non-enforceable, since any miner in any assumed pool can always just steal the block reward instead of following the rules set up by the pool. COMPACT TRANSACTIONS SpreadCoin uses a more compact representation for signatures in transactions. SpreadCoin as well as Bitcoin uses ECDSA signatures. While bitcoin keeps a copy of the public key of the corresponding signature around, SpreadCoin ommits this by recovering the public key on the fly directly from the signature. This way it is not necessary to keep the public key of every ECDSA signature in the blockchain, so this leads to *smaller transactions and hence a smaller blockchain (at the cost of a few CPU cycles more). (*reduction in size of transaction from 139 or 107 bytes in Bitcoin to 67 bytes in SpreadCoin.) SMOOTH HALVING Unlike Bitcoin, there are no abrupt reward halvings in SpreadCoin. Block reward is smoothly decreasing over time. UNIQUE DESIGN WITH IN-WALLET VANITYGEN One of the first apps to be built into the wallet is the vanity generator (or vanity gen) which allows anyone to create personalised payment addresses. The easy to use wallet lets you search through trillions of payment addresses allowing you to find one or multiple vanity addresses, which are then stored safely along with the private keys on your own computer - and nowhere else. Searching using the vanity gen is probabilistic, so the amount of time required to find your chosen address patterns depends on how complex the pattern is, the speed of your computer, and a little bit of luck. You can use the vanity gen for a bit of fun, to make your address standout from the crowd or to create a link to a brand, business or other organisation. You can even search for addresses that others might be willing to buy from you. SpreadCoin is a new cryptocurrency which is more decentralized than Bitcoin. It prevents centralization of hashing power in pools, which is one of the main concerns of Bitcoin security. SpreadCoin was fairly launched on 29 July 2014, 9:00 UTC with no premine.
JonathanBerkeley / QuackQuick Universal Anti-Cheat Kit. A collection of software aimed at demonstrating anti-cheat functionality & providing tools to aid anti-cheat development.
