Introduction to security via password policies

Security is an enormously complicated topic and it has a surprisingly large number of subtopics.  Security, at the 10,000 meters level, is all about making sure that a person or program (the privileged user) that should have access to some data, information, program, system or physical location (the asset) can obtain such access reasonably quickly and easily, with a common caveat that such access is logged and recorded.  Every other individual or program (the attacker) that may deliberately or accidentally attempt to obtain access is "satisfactory" denied, with a similar caveat that as much information as possible about the denied access is also logged and recorded. Here we explore how and why corporations rely on passwords.