67 lines
2.9 KiB
Handlebars
67 lines
2.9 KiB
Handlebars
# bigint-mod-arith
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Some extra functions to work with modular arithmetics using native JS (stage 3) implementation of BigInt. 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).
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If you are looking for a cryptographically-secure random generator and for strong probable primes (generation and testing), you
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may be interested in [bigint-secrets](https://github.com/juanelas/bigint-secrets)
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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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## Installation
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bigint-mod-arith is distributed for [web browsers and/or webviews supporting
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BigInt](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt#Browser_compatibility)
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as an ES6 module or an IIFE file; and for Node.js (>=10.4.0), as a CJS module.
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bigint-mod-arith can be imported to your project with `npm`:
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```bash
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npm install bigint-mod-arith
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```
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NPM installation defaults to the ES6 module for browsers and the CJS one for Node.js.
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For web browsers, you can also directly download the minimised version of the [IIFE file](https://raw.githubusercontent.com/juanelas/bigint-mod-arith/master/dist/bigint-mod-arith-latest.browser.min.js) or the [ES6 module](https://raw.githubusercontent.com/juanelas/bigint-mod-arith/master/dist/bigint-mod-arith-latest.browser.mod.min.js) from GitHub.
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## Usage example
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With node js:
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```javascript
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const bigintModArith = require('bigint-mod-arith');
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/* Stage 3 BigInts with value 666 can be declared as BigInt('666')
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or the shorter new no-so-linter-friendly syntax 666n.
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Notice that you can also pass a number, e.g. BigInt(666), but it is not
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recommended since values over 2**53 - 1 won't be safe but no warning will
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be raised.
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*/
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let a = BigInt('5');
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let b = BigInt('2');
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let n = BigInt('19');
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console.log(bigintCryptoUtils.modPow(a, b, n)); // prints 6
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console.log(bigintCryptoUtils.modInv(BigInt('2'), BigInt('5'))); // prints 3
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console.log(bigintCryptoUtils.modInv(BigInt('3'), BigInt('5'))); // prints 2
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```
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From a browser, you can just load the module in a html page as:
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```html
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<script type="module">
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import * as bigintModArith from 'bigint-mod-arith-latest.browser.mod.min.js';
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let a = BigInt('5');
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let b = BigInt('2');
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let n = BigInt('19');
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console.log(bigintModArith.modPow(a, b, n)); // prints 6
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console.log(bigintModArith.modInv(BigInt('2'), BigInt('5'))); // prints 3
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console.log(bigintModArith.modInv(BigInt('3'), BigInt('5'))); // prints 2
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</script>
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```
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# bigint-mod-arith JS Doc
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{{>main}}
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* * * |