generateKeypair.js

/**
 * This module will generate a public and private keypair and save to current directory
 *
 * Make sure to save the private key elsewhere after generated!
 */
const crypto = require("crypto");
const fs = require("fs");

function genKeyPair() {
  // Generates an object where the keys are stored in properties `privateKey` and `publicKey`
  const keyPair = crypto.generateKeyPairSync("rsa", {
    modulusLength: 4096, // bits - standard for RSA keys
    publicKeyEncoding: {
      type: "pkcs1", // "Public Key Cryptography Standards 1"
      format: "pem", // Most common formatting choice
    },
    privateKeyEncoding: {
      type: "pkcs1", // "Public Key Cryptography Standards 1"
      format: "pem", // Most common formatting choice
    },
  });

  // Write the keypair also the current directory
  fs.access(`./`, fs.F_OK, (err) => {
    if (!err) {
      if (process.argv.length > 2) {
        const keyName = process.argv[2];
        fs.writeFileSync(`./id_rsa_pub_${keyName}.pem`, keyPair.publicKey);
        fs.writeFileSync(`./id_rsa_priv_${keyName}.pem`, keyPair.privateKey);
      } else {
        fs.writeFileSync(`./id_rsa_pub.pem`, keyPair.publicKey);
        fs.writeFileSync(`./id_rsa_priv.pem`, keyPair.privateKey);
      }
    }
  });
}

// Generate the keypair
genKeyPair();