110 lines
5.2 KiB
Markdown
110 lines
5.2 KiB
Markdown
[](https://opensource.org/licenses/MIT)
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[](https://standardjs.com)
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[](https://github.com/juanelas/bigint-crypto-utils/actions?query=workflow%3A%22Node+CI%22)
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[](https://coveralls.io/github/juanelas/bigint-crypto-utils?branch=master)
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# bigint-crypto-utils
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Arbitrary precision modular arithmetic, cryptographically secure random numbers and strong probable prime generation/testing.
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It relies on the native JS implementation of ([BigInt](https://tc39.es/ecma262/#sec-bigint-objects)). It can be used by any [Web Browser or webview supporting BigInt](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt#Browser_compatibility) and with Node.js (>=10.4.0). The bundles can be imported directly by the browser or in Angular projects, React apps, Node.js, etc.
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Secure random numbers are generated using the native crypto implementation of the browsers ([Web Cryptography API](https://w3c.github.io/webcrypto/)) or [Node.js Crypto](https://nodejs.org/dist/latest/docs/api/crypto.html)). Strong probable prime generation and testing use Miller-Rabin primality tests and are automatically sped up using parallel workers both in browsers and Node.js.
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> The operations supported on BigInts are not constant time. BigInt can be therefore **[unsuitable for use in cryptography](https://www.chosenplaintext.ca/articles/beginners-guide-constant-time-cryptography.html).** Many platforms provide native support for cryptography, such as [Web Cryptography API](https://w3c.github.io/webcrypto/) or [Node.js Crypto](https://nodejs.org/dist/latest/docs/api/crypto.html).
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## Usage
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`bigint-crypto-utils` can be imported to your project with `npm`:
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```console
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npm install bigint-crypto-utils
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```
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Then either require (Node.js CJS):
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```javascript
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const bigintCryptoUtils = require('bigint-crypto-utils')
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```
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or import (JavaScript ES module):
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```javascript
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import * as bigintCryptoUtils from 'bigint-crypto-utils'
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```
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The appropriate version for browser or node is automatically exported.
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`bigint-crypto-utils` **CANNOT BE POLYFILLED** to suport older JS version (\< ES2020). If you are using webpack/babel to create your production bundles, you should target only the most modern browsers. For instance, for **React** apps created with [`create-react-app`](https://create-react-app.dev/), you should edit your `package.json` and modify the `browserList` so that it only targets the latest browsers (play with the number of versions that do not need polyfilling):
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```json
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"browserslist": {
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"production": [
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"last 1 chrome version",
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"last 1 firefox version",
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"last 1 safari version"
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],
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"development": [
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"last 1 chrome version",
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"last 1 firefox version",
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"last 1 safari version"
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]
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}
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```
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Also, notice that [BigInt implementation is ES2020](https://tc39.es/ecma262/#sec-bigint-objects). In order to use it with TypeScript you need to set `target` to `ES2020` in your project's `tsconfig.json`.
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If you are using Angular, since this library uses node typings, you should also add them to the `angularCompilerOptions` in your `tsconfig.json`:
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```json
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"angularCompilerOptions": {
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"types": ["node", ...]
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...
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}
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```
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You can also download the [IIFE bundle](https://raw.githubusercontent.com/juanelas/bigint-crypto-utils/master/dist/bundles/bigint-crypto-utils.iife.js), the [ESM bundle](https://raw.githubusercontent.com/juanelas/bigint-crypto-utils/master/dist/bundles/bigint-crypto-utils.esm.js) or the [UMD bundle](https://raw.githubusercontent.com/juanelas/bigint-crypto-utils/master/dist/bundles/bigint-crypto-utils.umd.js) and manually add it to your project, or, if you have already imported `bigint-crypto-utils` to your project, just get the bundles from `node_modules/bigint-crypto-utils/dist/bundles/`.
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An example of usage could be:
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```typescript
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/* A BigInt with value 666 can be declared calling the bigint constructor as
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BigInt('666') or with the shorter 666n.
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Notice that you can also pass a number to the constructor, e.g. BigInt(666).
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However, it is not recommended since values over 2**53 - 1 won't be safe but
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no warning will be raised.
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*/
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const a = BigInt('5')
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const b = BigInt('2')
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const n = 19n
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console.log(bigintCryptoUtils.modPow(a, b, n)) // prints 6
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console.log(bigintCryptoUtils.modInv(2n, 5n)) // prints 3
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console.log(bigintCryptoUtils.modInv(BigInt('3'), BigInt('5'))) // prints 2
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console.log(bigintCryptoUtils.randBetween(2n ** 256n)) // Prints a cryptographically secure random number between 1 and 2**256 bits.
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async function primeTesting (): void {
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// Output of a probable prime of 2048 bits
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console.log(await bigintCryptoUtils.prime(2048))
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// Testing if a number is a probable prime (Miller-Rabin)
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const number = 27n
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const isPrime = await bigintCryptoUtils.isProbablyPrime(number)
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if (isPrime === true) {
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console.log(`${number} is prime`)
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} else {
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console.log(`${number} is composite`)
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}
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}
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primeTesting()
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```
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## API reference documentation
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[Check the API](./docs/API.md)
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