如何生成在 node.js 和浏览器中都有效的 RSA 对

Question

I want to achieve RSA encryption between a node server and a browser. So far I've used node-rsa on the server:

const RSA = require("node-rsa")
const key = new RSA({b: 512});
console.log(key.exportKey("public"))

And it looks like this:

-----BEGIN PUBLIC KEY-----
MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAMSZQk6XJbPTr/0bY1OYQUPkUXfsC4K8
iPywjTpIDLZhw341cxPaiI0dxkP/GLvG+03xqboFMRFJbs4L5aXA9x0CAwEAAQ==
-----END PUBLIC KEY-----

How can I do the same thing in browser.
PS I've tried SubtleCrypto API put I can't figure out how to produce a similar format as in node-rsa.

Answer 1

What you see is a PEM encoded SubjectPublicKeyInfo or "spki" for short. Helpfully, the official SuptleCrypto API offers an example code snippet that shows how to create the binary structure and put it in PEM format.

The node-rsa NodeJS library incorrectly calls this 'pkcs8' or more specifically 'pkcs8-public' (at least, that's what I can grok from their documentation). I've created bug report 208 which you can vote on.

Answer 2

I've found this code for the client side that can generate an RSA pair and export the public key (for some reason it doesn't work for the private one).

async function exportCryptoKey(key) {
    const exportedAsBase64 = window.btoa(String.fromCharCode.apply(null, new Uint8Array(await window.crypto.subtle.exportKey("spki", key))))
    return `-----BEGIN PUBLIC KEY-----\n${exportedAsBase64}\n-----END PUBLIC KEY-----`
}
async function main(){
    keyPair = await window.crypto.subtle.generateKey({
            name: "RSA-OAEP",
            modulusLength: 2048,
            publicExponent: new Uint8Array([1, 0, 1]),
            hash: "SHA-256",
        }, true, ["encrypt", "decrypt"])
    console.log(await exportCryptoKey(keyPair.publicKey))
}
main()

Answer 3

You need to install browserify for using nodejs require() method in browser.

run this in your terminal:

npm install browserify

then,

browserify index.js //"your current js file_name// -o bundle.js

now use this bundle.js in your html