my-idlers/node_modules/browserify-aes/streamCipher.js

var aes = require('./aes')
var Buffer = require('safe-buffer').Buffer
var Transform = require('cipher-base')
var inherits = require('inherits')

function StreamCipher (mode, key, iv, decrypt) {
  Transform.call(this)

  this._cipher = new aes.AES(key)
  this._prev = Buffer.from(iv)
  this._cache = Buffer.allocUnsafe(0)
  this._secCache = Buffer.allocUnsafe(0)
  this._decrypt = decrypt
  this._mode = mode
}

inherits(StreamCipher, Transform)

StreamCipher.prototype._update = function (chunk) {
  return this._mode.encrypt(this, chunk, this._decrypt)
}

StreamCipher.prototype._final = function () {
  this._cipher.scrub()
}

module.exports = StreamCipher