General security principles

…Let's quickly review the primary security principles.…These principles are covered in more depth in the…Fundamentals of Programming, Web Security course that I mentioned earlier.…The first principle is least privilege.…The principle of least privilege means giving a user account only…those privileges which are essential to that user's work, nothing more.…Users in human resources shouldn't be able to see accounting information,…and users in accounting shouldn't be able to see human resources information.…But we're not just talking about user privileges.…Code has access privileges too.…

Code should be limited in what it exposes and what it accesses.…In object-oriented programming, this means controlling…the visibility of class variables and functions.…For example, if a function in a PHP class object is only used by…that class object, then it does not need to be callable from outside the class.…The second principle is that simple is more secure.…The larger and more complex that a system…becomes, the harder it becomes to secure it.…