NodeJS Generate Valid PEM keys for Signing and Verifying messages

Question

Context

From the NodeJS documentation on TLS/SSL for Node v10.9.0 (2018-AUG)

https://nodejs.org/api/tls.html#tls_tls_ssl_concepts

openssl genrsa -out ryans-key.pem 2048

Will produce:

-----BEGIN RSA PRIVATE KEY-----
base64 encoded magic here...
-----END RSA PRIVATE KEY-----

Which I can then successfully use the Sign class to cryptographically sign a message:

https://nodejs.org/api/crypto.html#crypto_class_sign

const crypto = require('crypto');
const sign = crypto.createSign('RSA-SHA256');

sign.update('some data to sign');

const privateKey = `Insert magic value from above`;
console.log(sign.sign(privateKey, 'base64'));

I have tried the following with no success:

const crypto = require('crypto');
const dhke = crypto.createDiffieHellman(2048);
dhke.generateKeys();
const private_pem = `-----BEGIN RSA PRIVATE KEY-----
${dhke.getPrivateKey('base64')}
-----END RSA PRIVATE KEY-----`;
console.log(private_pem);

const sign = crypto.createSign('RSA-SHA256');
sign.update('some data to sign');

const signature = sign.sign(private_pem, 'base64');
console.log(signature);

Getting the following error:

Error: error:0D07207B:asn1 encoding routines:ASN1_get_object:header too long
    at Sign.sign (internal/crypto/sig.js:84:26)
...

The Question

How do I use the crypto library in NodeJS to achieve what openssl command line tool is performing (or another NPM module) to create a valid PEM formatted public/private key-pair which is required by the Sign class?

Similar unresolved questions

• Generate Key for signing within nodejs

Solution

Here is the start to finish working solution thanks to the accepted answer from JacobTDC where NodeJS v10.12.0 added this feature.

const crypto = require('crypto'); const sign = crypto.createSign('RSA-SHA256');

sign.update('some data to sign');

// $ openssl genrsa -out ryans-key.pem 2048 
// const privateKey = `Insert magic value from above`;

const { generateKeyPairSync } = require('crypto'); 
const { publicKey, privateKey } = generateKeyPairSync('rsa', 
{   modulusLength: 2048,  // the length of your key in bits   
    publicKeyEncoding: {
      type: 'spki',       // recommended to be 'spki' by the Node.js docs
      format: 'pem'   
    },   
    privateKeyEncoding: {
      type: 'pkcs8',      // recommended to be 'pkcs8' by the Node.js docs
      format: 'pem',
      //cipher: 'aes-256-cbc',   // *optional*
      //passphrase: 'top secret' // *optional*   
  } 
}); 
console.log(privateKey); 
console.log(sign.sign(privateKey, 'base64'));

Answer 1

As of Node.js v10.12.0, you can use crypto.generateKeyPair and crypto.generateKeyPairSync.

I have provided an example from the Node.js docs below (with added comments):

const { generateKeyPairSync } = require('crypto');
const { publicKey, privateKey } = generateKeyPairSync('rsa', {
  modulusLength: 4096,  // the length of your key in bits
  publicKeyEncoding: {
    type: 'spki',       // recommended to be 'spki' by the Node.js docs
    format: 'pem'
  },
  privateKeyEncoding: {
    type: 'pkcs8',      // recommended to be 'pkcs8' by the Node.js docs
    format: 'pem',
    cipher: 'aes-256-cbc',   // *optional*
    passphrase: 'top secret' // *optional*
  }
});