brewkit.rb changes ENV destructively, so lets not do that everytime a formula
is required. Now it's possible for other tools to require a formula
description without worrying about side-effects.
MCrypt is a replacement for the old crypt() package and crypt(1) command, with
extensions. It allows developers to use a wide range of encryption functions,
without making drastic changes to their code. It allows users to encrypt
files or data streams without having to be cryptographers. Above all, it
allows you to have some really neat code on your machine. :)