Passwords have been used for bags of years as a means of anecdotic ourselves to others and in more recent times, to computers. It’s a simple abstraction – a shared piece of advice kept secret amid individuals and used to “prove” identity.

Passwords in an IT ambience emerged in the 1960s with mainframe computers – large centrally operated computers with remote “terminals” for user access. They’re now used for aggregate from the PIN we enter at an ATM, to logging in to our computers and assorted websites.

But why do we need to “prove” our appearance to the systems we access? And why are passwords so hard to get right?

What makes a good password?

Until almost recently, a good countersign might have been a word or phrase of as little as six to eight characters. But we now have minimum length guidelines. This is because of “entropy.”

When talking about passwords, anarchy is the admeasurement of predictability. The maths behind this isn’t complex, but let’s appraise it with an even simpler measure: the number of accessible passwords, sometimes referred to as the “password space.”

If a one-character countersign only contains one lowercase letter, there are only 26 accessible passwords (“a” to “z”). By including uppercase letters, we access our countersign space to 52 abeyant passwords.

The countersign space continues to expand as the length is added and other appearance types are added.