pbcrypt-node.js

'use strict'
const crypto = require('crypto')
const {promisify} = require('util')

let pwtokey = (pass, salt='', iter=100) =>
  promisify(crypto.pbkdf2)(pass, salt, iter, 16, 'sha256')

let encrypt = async (key, msg) => {
  let iv = await promisify(crypto.randomBytes)(16)
  let ctx = crypto.createCipheriv('aes-128-gcm', key, iv)
  return Buffer.concat([
    iv,
    ctx.update(msg, 'utf8'),
    ctx.final(),
    ctx.getAuthTag()
  ]).toString('base64')
}

let decrypt = async (key, msg) => {
  let buf = Buffer.from(msg, 'base64')
  let ctx = crypto.createDecipheriv('aes-128-gcm', key, buf.slice(0, 16))
  ctx.setAuthTag(buf.slice(-16))
  return ctx.update(buf.slice(16, -16), null, 'utf8') + ctx.final('utf8')
}

module.exports = {
  pwtokey,
  encrypt,
  decrypt,
}

pbcrypt-web.js

'use strict'

let str2buf = (e => e.encode.bind(e))(new TextEncoder('utf-8'))
let buf2str = (e => e.decode.bind(e))(new TextDecoder('utf-8'))

let asc2buf = asc => Uint8Array.from(atob(asc), s => s.charCodeAt(0))
let buf2asc = buf => btoa(String.fromCharCode.apply(null, new Uint8Array(buf)))

let pwtokey = async (pass, salt='', iter=100) =>
  crypto.subtle.deriveKey({
    name: 'PBKDF2',
    salt: str2buf(salt),
    iterations: iter,
    hash: 'SHA-256'
  }, await crypto.subtle.importKey(
    'raw', str2buf(pass),
    {name: 'PBKDF2'}, false, ['deriveKey']
  ), {
    name: 'AES-GCM',
    length: 128
  }, false, ['encrypt', 'decrypt'])

let decrypt = async (key, msg) => {
  let buf = await asc2buf(msg)
  return buf2str(await crypto.subtle.decrypt({
    name: 'AES-GCM',
    iv: buf.slice(0, 16)
  }, key, buf.slice(16)))
}

let encrypt = async (key, msg) => {
  let iv = crypto.getRandomValues(new Uint8Array(16))
  let cm = await crypto.subtle.encrypt({
    name: 'AES-GCM', iv
  }, key, str2buf(msg))
  let buf = new Uint8Array(cm.byteLength + 16)
  buf.set(iv)
  buf.set(new Uint8Array(cm), 16)
  return buf2asc(buf)
}