rsa-compat.js/lib/generate-privkey-forge.js

// Copyright 2016-2018 AJ ONeal. All rights reserved
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
'use strict';

var Keypairs = require('keypairs');

module.exports = function (bitlen, exp) {
  var k = require('node-forge').pki.rsa
    .generateKeyPair({ bits: bitlen || 2048, e: exp || 0x10001 }).privateKey;
  var jwk = {
    kty: "RSA"
  , n: _toUrlBase64(k.n)
  , e: _toUrlBase64(k.e)
  , d: _toUrlBase64(k.d)
  , p: _toUrlBase64(k.p)
  , q: _toUrlBase64(k.q)
  , dp: _toUrlBase64(k.dP)
  , dq: _toUrlBase64(k.dQ)
  , qi: _toUrlBase64(k.qInv)
  };
  return {
    publicKeyPem: Keypairs._exportSync({ jwk: jwk, public: true })
  , privateKeyPem: Keypairs._exportSync({ jwk: jwk })
  , privateKeyJwk: jwk
  , publicKeyJwk: {
      kty: jwk.kty
    , n: jwk.n
    , e: jwk.e
    }
  };
};

function _toUrlBase64(fbn) {
  var hex = fbn.toRadix(16);
  if (hex.length % 2) {
    // Invalid hex string
    hex = '0' + hex;
  }
  while ('00' === hex.slice(0, 2)) {
    hex = hex.slice(2);
  }
  return Buffer.from(hex, 'hex').toString('base64')
    .replace(/\+/g, "-")
    .replace(/\//g, "_")
    .replace(/=/g,"")
  ;
}

if (require.main === module) {
  var keypair = module.exports(2048, 0x10001);
  console.info(keypair.privateKeyPem);
  console.warn(keypair.publicKeyPem);
  //console.info(keypair.privateKeyJwk);
  //console.warn(keypair.publicKeyJwk);
}