var xor = require('../xor');
exports.encrypt = function (self, block) {
  var data = xor(block, self._prev);
  self._prev = self._cipher.encryptBlock(data);
  return self._prev;
};
exports.decrypt = function (self, block) {
  var pad = self._prev;
  self._prev = block;
  var out = self._cipher.decryptBlock(block);
  return xor(out, pad);
};