convertPbkdf2.js

/*
 * Converts a PBKDF2 hash generated by PBKDF2PasswordEncryptor to PHC format
 */
const digest = 'sha1'

const convert = origHash => {
  const buf = Buffer.from(origHash, 'base64')

  const keylenBits = parseInt(buf.slice(0, 4).toString('hex'), 16)
  const keylen = keylenBits / 8

  const iterations = parseInt(buf.slice(4, 8).toString('hex'), 16)

  const salt = buf.slice(8, 16).toString('base64').replace(/=/g, '')

  const hash = buf.slice(16).toString('base64').replace(/=/g, '')

  return `$pbkdf2-${digest}$i=${iterations},l=${keylen}$${salt}$${hash}`
}

const h = 'AAAAoAAB9ABzWnS2vspWtgNxyaXRnXX4Kg6IwSd2A+3V8WuZ' // plaintext value = 'changeme'
const converted = convert(h)
console.log(converted)