Nodejs encrypt decrypt keygen asymmetric

encrypt_decrypt_asym.js

const crypto = require('crypto')
const path = require('path')
const fs = require('fs')


const { writeFileSync } = require('fs')
const { generateKeyPairSync } = require('crypto')

function generateKeys() {
  const { privateKey, publicKey } = generateKeyPairSync('rsa', {
    modulusLength: 4096,
    publicKeyEncoding: {
      type: 'pkcs1',
      format: 'pem',
    },
    privateKeyEncoding: {
      type: 'pkcs1',
      format: 'pem',
      cipher: 'aes-256-cbc',
      passphrase: '',
    },
  })

  writeFileSync('private.pem', privateKey)
  writeFileSync('public.pem', publicKey)
}

generateKeys()

function encrypt(toEncrypt, relativeOrAbsolutePathToPublicKey) {
  const absolutePath = path.resolve(relativeOrAbsolutePathToPublicKey)
  const publicKey = fs.readFileSync(absolutePath, 'utf8')
  const buffer = Buffer.from(toEncrypt, 'utf8')
  const encrypted = crypto.publicEncrypt(publicKey, buffer)
  return encrypted.toString('base64')
}

function decrypt(toDecrypt, relativeOrAbsolutePathtoPrivateKey) {
  const absolutePath = path.resolve(relativeOrAbsolutePathtoPrivateKey)
  const privateKey = fs.readFileSync(absolutePath, 'utf8')
  const buffer = Buffer.from(toDecrypt, 'base64')
  const decrypted = crypto.privateDecrypt(
    {
      key: privateKey.toString(),
      passphrase: '',
    },
    buffer,
  )
  return decrypted.toString('utf8')
}

const enc = encrypt('pik@chu', `public.pem`)
console.log('enc', enc)

const dec = decrypt(enc, `private.pem`)
console.log('dec', dec)