Use window.crypto in nodejs code

Question

I am trying to use the window.crypto.getRandomValues method in a nodejs script. From my understanding there is no window element when I run a simple code like this in node:

var array = new Uint32Array(10);
window.crypto.getRandomValues(array);

Which is why I get this error:

ReferenceError: window is not defined

How can I use this method in my code?

Thanks

In "window" is only used in web development Javascript, not node.js. Use globalThis to replace window. — Jake, Feb 21 '22 at 22:46

score 20 · Accepted Answer · answered Sep 08 '14 at 13:40

20

You can use the built-in crypto module instead. It provides both a crypto.randomBytes() as well as a crypto.pseudoRandomBytes().

However it should be noted that these methods give you a Buffer object, you cannot pass in a Uint32Array or similar, so the API is a bit different.

answered Sep 08 '14 at 13:40

mscdex

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ok thanks. How can I turn the buffer object returned as a simple 256-bit number? – Spearfisher Sep 08 '14 at 13:55
You'd have to use some javascript big number/integer library to convert the bytes to a number that large. – mscdex Sep 08 '14 at 14:05
3

Note that as of version 7.10.0 of Node, there is a [`crypto.randomFillSync()`](https://nodejs.org/docs/latest/api/crypto.html#crypto_crypto_randomfillsync_buffer_offset_size) function in NodeJS which allows you to pass a `TypedArray`. – Heretic Monkey Jun 05 '18 at 21:17

score 11 · Answer 2 · answered Mar 16 '16 at 01:21

11

You can use this module which is the same as the window element: get-random-values

Install it:

npm install get-random-values --save

Use it:

var getRandomValues = require('get-random-values');

var array = new Uint32Array(10);
getRandomValues(array);

answered Mar 16 '16 at 01:21

Mohamed Mansour

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This isn't the same as the window element, this use nodejs crypto – Clint Aug 26 '16 at 03:26
TypeError: expected Uint8Array – Pawel Cioch Sep 14 '16 at 17:14
This should be the correct answer, with a simple addition, this can behave the same as the browser version. – Phil Dec 30 '20 at 20:05

score 8 · Answer 3 · edited Sep 11 '21 at 15:29

8

const crypto = require('crypto').webcrypto;

let a = new Uint8Array(24);
console.log(crypto.getRandomValues(a));

This works almost exactly like the one in the browser, by adding webcrypto to the end of requrie('crypto');.

edited Sep 11 '21 at 15:29

Smart Manoj

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answered Mar 18 '21 at 14:09

Wolfy

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Should note that crypto.webcrypto is only available in Node.js 15.0.0+. LTS versions do not yet support it. – Robert G. Schaffrath Jun 04 '21 at 12:31
2

Node 16 is LTS now and this makes it a great answer! – Skocdopole Nov 29 '21 at 12:14
Typescript makes using this harder than expected https://github.com/denoland/node_deno_shims/issues/56 ... to bypass I used `const crypto = webcrypto as any` – Ray Foss Jan 31 '22 at 14:57

score 1 · Answer 4 · answered Feb 02 '22 at 18:11

Here is how to use it in Node 16 with TypeScript. I'm hijacking the web types and overriding the @types/node type, which are missing webcrypto.

import { webcrypto } from 'crypto'
const crypto = webcrypto as unknown as Crypto
const random = crypto.getRandomValues(new Uint8Array(24))

This sandbox will work in Node 16, but stackblitz won't release node 16 for another couple months. https://stackblitz.com/edit/koa-starter-wychx9?file=package.json

Issue: github.com/denoland/node_deno_shims/issues/56

Use window.crypto in nodejs code

4 Answers4

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